Nebraska Supreme Court Online Library
www.nebraska.gov/apps-courts-epub/
01/25/2019 09:13 AM CST




                                                        - 856 -
                                  Nebraska Supreme Court A dvance Sheets
                                          301 Nebraska R eports
                                                  STATE v. TUCKER
                                                  Cite as 301 Neb. 856




                                        State of Nebraska, appellee, v.
                                         Carlos A. Tucker, appellant.
                                                    ___ N.W.2d ___

                                        Filed December 14, 2018.   No. S-17-926.

                1.	 Rules of Evidence: Appeal and Error. An appellate court reviews
                    for abuse of discretion a trial court’s evidentiary rulings on relevance,
                    whether the probative value of evidence is substantially outweighed by
                    the danger of unfair prejudice, and the sufficiency of a party’s founda-
                    tion for admitting evidence.
                2.	 Expert Witnesses: Appeal and Error. The standard for reviewing the
                    admissibility of expert testimony is abuse of discretion.
                3.	 Convictions: Evidence: Appeal and Error. In reviewing a criminal
                    conviction for a sufficiency of the evidence claim, whether the evidence
                    is direct, circumstantial, or a combination thereof, the standard is the
                    same: An appellate court does not resolve conflicts in the evidence, pass
                    on the credibility of witnesses, or reweigh the evidence; such matters
                    are for the finder of fact. The relevant question for an appellate court
                    is whether, after viewing the evidence in the light most favorable to the
                    prosecution, any rational trier of fact could have found the essential ele-
                    ments of the crime beyond a reasonable doubt.
                4.	 Sentences: Appeal and Error. An appellate court will not disturb a sen-
                    tence imposed within the statutory limits absent an abuse of discretion
                    by the trial court.
                5.	 Evidence: Words and Phrases. Evidence is relevant if it tends in any
                    degree to alter the probability of a material fact.
                6.	 Rules of Evidence. Under Neb. Evid. R. 403, Neb. Rev. Stat. § 27-403
                    (Reissue 2016), relevant evidence may be excluded if its probative value
                    is substantially outweighed by the danger of unfair prejudice.
                7.	 Evidence. Most, if not all, evidence offered by a party is calculated to
                    be prejudicial to the opposing party.
                8.	 Evidence: Words and Phrases. Unfair prejudice means an undue tend­
                    ency to suggest a decision based on an improper basis.
                                     - 857 -
              Nebraska Supreme Court A dvance Sheets
                      301 Nebraska R eports
                              STATE v. TUCKER
                              Cite as 301 Neb. 856

  9.	 ____: ____. Unfair prejudice speaks to the capacity of some concededly
      relevant evidence to lure the fact finder into declaring guilt on a ground
      different from proof specific to the offense charged, commonly on an
      emotional basis.
10.	 Witnesses: Juries: Appeal and Error. The credibility and weight of
      witness testimony are for the jury to determine, and witness credibility
      is not to be reassessed on appellate review.
11.	 Sentences: Appeal and Error. Where a sentence imposed within the
      statutory limits is alleged on appeal to be excessive, the appellate court
      must determine whether a sentencing court abused its discretion in con-
      sidering and applying the relevant factors as well as any applicable legal
      principles in determining the sentence to be imposed.
12.	 Sentences. In determining a sentence to be imposed, relevant factors
      customarily considered and applied are the defendant’s (1) age, (2) men-
      tality, (3) education and experience, (4) social and cultural background,
      (5) past criminal record or record of law-abiding conduct, and (6) moti-
      vation for the offense, as well as (7) the nature of the offense and (8) the
      amount of violence involved in the commission of the crime.
13.	 ____. The appropriateness of a sentence is necessarily a subjective judg-
      ment and includes the sentencing judge’s observation of the defendant’s
      demeanor and attitude and all the facts and circumstances surrounding
      the defendant’s life.
14.	 ____. Generally, it is within a trial court’s discretion to direct that
      sentences imposed for separate crimes be served either concurrently or
      consecutively.

   Appeal from the District Court for Lancaster County: Darla
S. Ideus, Judge. Affirmed.
  Joseph D. Nigro, Lancaster County Public Defender, and
John C. Jorgensen for appellant.
  Douglas J. Peterson, Attorney General, Erin E. Tangeman,
and, on brief, Sarah E. Marfisi for appellee.
  Heavican, C.J.,            Cassel,      Stacy,     Funke,       Papik,     and
Freudenberg, JJ.
  Papik, J.
  Carlos A. Tucker appeals his convictions and sentences for
one count of first degree sexual assault of a child and two
                              - 858 -
           Nebraska Supreme Court A dvance Sheets
                   301 Nebraska R eports
                        STATE v. TUCKER
                        Cite as 301 Neb. 856

counts of incest, related to an incident with his girlfriend’s
children. Evidence at trial showed that Tucker engaged in
sex acts with M.T., age 11, and that M.T. and her two broth-
ers, E.T., age 12, and R.T., age 10, engaged in sex acts upon
Tucker’s instructions. The main issue presented by this appeal
is whether the district court abused its discretion in admitting
“Y-STR” DNA evidence over Tucker’s objections. We con-
clude that it did not. We further reject Tucker’s contentions that
the evidence was insufficient to support his convictions and
that the district court imposed excessive sentences. Finding no
error, we affirm.
                       BACKGROUND
Charges Against Tucker.
   The State charged Tucker with one count of first degree
sexual assault of a child in violation of Neb. Rev. Stat.
§ 28-319.01(2) (Reissue 2016) and two counts of incest with
a person under 18 years of age in violation of Neb. Rev. Stat.
§ 28-703 (Reissue 2008). The charges arose out of allegations
by M.T., E.T., and R.T. that Tucker, their mother’s live-in
­boyfriend, had engaged in sex acts with M.T. and that M.T. had
 engaged in sex acts with E.T. and R.T. after being instructed to
 do so by Tucker.
Pretrial Proceedings.
   Prior to trial, Tucker filed a motion in limine seeking
to exclude all evidence of Y-STR DNA testing pursuant to
Daubert v. Merrell Dow Pharmaceuticals, Inc., 509 U.S. 579,
113 S. Ct. 2786, 125 L. Ed. 2d 469 (1993), and Schafersman v.
Agland Coop, 262 Neb. 215, 631 N.W.2d 862 (2001) (Daubert/
Schafersman). He also alleged that such evidence would con-
fuse the jury and that its prejudicial effect would outweigh its
probative value.
   At a pretrial hearing on the motion, the district court heard
expert testimony by Shannen Bishop, a DNA analyst at the
University of Nebraska Medical Center (UNMC). Bishop testi-
fied concerning the Y-STR DNA analysis she conducted on
                               - 859 -
           Nebraska Supreme Court A dvance Sheets
                   301 Nebraska R eports
                         STATE v. TUCKER
                         Cite as 301 Neb. 856

DNA found on the interior of the shorts M.T. wore on the
day of the alleged assault. Bishop also explained the origins,
mechanics, and limitations of Y-STR DNA testing, as well as
the extent to which it is accepted in the scientific community.
Bishop testified that Y-STR DNA testing looks only at the male
chromosome portion of DNA, while autosomal DNA testing
looks at all 23 chromosomes inherited by each person. She
dismissed as irrelevant several journal articles submitted by
Tucker purporting to discredit the application of Y-STR DNA
testing to small ethnic populations. Bishop explained that the
articles examined very small, specific sample sizes and that
Y-STR DNA science has improved since the articles were pub-
lished in the early 2000’s. She further pointed out that the U.S.
Y-STR database, which she used in her analysis, was not even
established when most of the articles were written.
   Following the hearing, the district court denied Tucker’s
motion in limine. It applied the Daubert/Schafersman analyti-
cal framework and determined the reasoning and methodology
behind Bishop’s opinions and Y-STR DNA testing to be valid
and reliable. The district court further rejected Tucker’s argu-
ment that the prejudicial effect of Y-STR DNA evidence out-
weighed its probative value.

Evidence at Trial.
   At the jury trial, M.T., E.T., and R.T. testified that on the day
at issue, their mother was at work and Tucker was home with
them. The children testified that Tucker, then age 31, invited
them to play a series of games in which he would give the
winner candy. The games began innocuously enough with the
children competing to be the last to laugh, but they progressed
to include the children undressing. In one game, the children
undressed and Tucker hid their clothes. In another, Tucker
instructed the children to switch clothing with one another.
   The children testified that after a series of these games,
Tucker directed them to the living room. Tucker instructed
the children to disrobe completely, and he played pornography
                              - 860 -
           Nebraska Supreme Court A dvance Sheets
                   301 Nebraska R eports
                        STATE v. TUCKER
                        Cite as 301 Neb. 856

on the television. The boys testified that Tucker told them to
masturbate. All three children testified that at some point while
they were in the living room, Tucker licked M.T.’s vagina, and
E.T. and R.T. testified that they followed Tucker’s instructions
to do the same. The three children testified that Tucker also
directed M.T. to put her mouth on his penis while, M.T. testi-
fied, he used his hand to move her head. All three children also
testified that M.T. complied with Tucker’s instructions to put
her mouth on E.T.’s and R.T.’s penises as well, with R.T. speci-
fying that M.T. “suck[ed]” on their penises. There was also
testimony that Tucker placed an electric toothbrush on M.T.’s
vagina. The children testified that they saw “white stuff” or
“clear stuff” come out of Tucker’s penis, which he wiped off
with a tissue or napkin. R.T. observed some of the fluid from
Tucker’s penis fall onto the carpet. M.T. and E.T. testified that
Tucker referred to their activities as “sex ed.”
   During cross-examination, which referenced previous inter-
views, it was revealed that the children’s testimony contained
some inconsistencies on such matters as the sequence of the
games, the objects of the games, their relative stages of undress
during portions of the games, who won each game, the content
of the pornography, the sequence of the sex acts, and whether
sex acts occurred involving M.T.’s breasts or two persons per-
forming sex acts with M.T. at the same time. However, each
child testified that on the day in question, M.T. performed fel-
latio on Tucker and both brothers upon Tucker’s instructions
and that Tucker performed cunnilingus on M.T.
   Contrary to Tucker’s instructions to the children not to dis-
close what happened, the children informed their mother. After
law enforcement was alerted, police conducted a search of the
residence the children shared with their mother and Tucker.
They found candy wrappers for the same type of candy the
children reported Tucker had given to them. A stain found on
the living room rug tested positive for semen. DNA testing
showed that the semen had the same genetic profile as Tucker
and that the probability of randomly selecting an unrelated
                              - 861 -
           Nebraska Supreme Court A dvance Sheets
                   301 Nebraska R eports
                        STATE v. TUCKER
                        Cite as 301 Neb. 856

individual with a DNA profile matching the sample was 1 in
752.4 quintillion. The State also introduced Y-STR DNA evi-
dence found on the shorts M.T. wore on the day of the alleged
offenses. This evidence is discussed in more detail in the sec-
tion below.
   Tucker testified in his own behalf. He denied engaging in
any sex acts with the children.

Y-STR DNA Evidence.
   The State called Bishop to testify regarding Y-STR DNA
testing. Tucker’s counsel made a continuing objection to the
Y-STR DNA testing and any opinions derived from such test-
ing based on Daubert/Schafersman, because such evidence
was “inherently unreliable and unfairly prejudicial and other-
wise not relevant.” The district court overruled the continu-
ing objection.
   Bishop testified that she is a forensic science DNA analyst
at UNMC and that she had performed Y-STR DNA testing on
extractions from the interior of M.T.’s shorts. Bishop stated
that Y-STR DNA testing was a method of looking only at the
male Y-chromosome. Bishop explained Y-STR DNA testing
is often used in sexual assault cases because it can identify a
male’s contribution to a sample, such as a vaginal swab, that
may have many more cells from a female contributor than a
male contributor. Bishop testified that UNMC has performed
Y-STR DNA analysis since the early 2000’s and that UNMC
has used the particular Y-STR DNA kit used in this case since
2012. Bishop stated that Y-STR DNA analysis is an accepted
forensic tool in the forensic analysis community that has been
available since the early 2000’s.
   Bishop explained that the Y-STR DNA testing process is
essentially the same as autosomal DNA testing, but admitted
that there is a great deal of difference between the discrimi-
natory power of autosomal DNA testing versus Y-STR DNA
testing. She testified that autosomal DNA testing can produce
results showing that a particular profile is extremely rare in the
                              - 862 -
           Nebraska Supreme Court A dvance Sheets
                   301 Nebraska R eports
                        STATE v. TUCKER
                        Cite as 301 Neb. 856

population, but because the same Y-STR DNA profile is passed
to all males in the same lineage and additionally may be pres-
ent in unrelated members of the general population, Y-STR
DNA testing results will not show that a particular profile is
as rare. She acknowledged that a coincidental random match
might occur one in several quintillion times with autosomal
DNA testing but one in a few thousand times with Y-STR
DNA testing.
   Bishop testified that Y-STR DNA testing identified Y-STR
DNA present on the interior of M.T.’s shorts and that it con-
sisted of a mixture of at least two male individuals. Bishop
testified that she could not determine what type of cell con-
tributed the Y-STR DNA profile to M.T.’s shorts or how it was
deposited there. However, she stated that the major Y-STR
DNA profile she found on the shorts matched Tucker at all
of the loci obtained and that, consequently, Tucker was not
excluded as a potential major source of the DNA tested.
   Bishop testified that to calculate the frequency of Tucker’s
Y-STR DNA profile within the population, it was necessary
to consult a database. Bishop testified and her report reflected
that according to the U.S. Y-STR database, the probability of
randomly selecting a second individual with the same Y-STR
DNA profile, given that Tucker expresses such a profile, was 1
in 1,842 for African Americans. Tucker does not dispute the he
is African American.
   Bishop’s report reflected that the U.S. Y-STR database was
maintained by a national institute in the forensic science field.
Bishop admitted that the U.S. Y-STR database had changed
since her analysis because it is always gaining contributors.
She further admitted that it was possible that the more indi-
viduals that contribute, the better the database will be at dis-
cerning the likelihood of a particular profile appearing in the
general population.
   A forensic scientist with the Nebraska State Patrol Crime
Laboratory’s biology unit also explained the statistical limita-
tions arising from the patrilineal recurrence of Y-STR DNA
                              - 863 -
           Nebraska Supreme Court A dvance Sheets
                   301 Nebraska R eports
                        STATE v. TUCKER
                        Cite as 301 Neb. 856

and the possible occurrence in the general population, con­
sistent with Bishop’s testimony.

Jury Verdict and Sentencing.
   The jury returned a verdict finding Tucker guilty on all
charges. The district court ordered a presentence investigation
report (PSR). The PSR reflected that Tucker, then age 33, had
a traumatic childhood. Tucker’s father was not involved in his
life, and he reported that he and his 10 siblings all have dif-
ferent fathers. Tucker grew up in an area where gang crime
and drugs were prevalent. He reported that his mother was a
drug user and that he “‘had to find ways to eat and live.’” As
a child, he witnessed his mother shoot her boyfriend, and he
developed post-traumatic stress disorder as a result. He has
also been diagnosed with paranoid schizophrenia, bipolar dis-
order, and manic depression.
   Tucker has been involved in criminal activity since his
youth. His criminal history includes a term of probation and
incarceration for forgery and escape and other jail terms of
considerable length for theft. His other offenses include a num-
ber of drug charges, false information, false reporting, failure
to appear, attempted tampering with a witness, and various
traffic offenses.
   Tucker had completed an associate degree in theology and
anthropology, and he wanted to continue his education. At the
time of the present offenses, he was an owner-employee of an
aquatic pet store. In the past, Tucker had worked as a dish-
washer, cook, and telemarketer. When he was not employed, he
supported himself by selling marijuana.
   The PSR noted that Tucker had refused to take responsibility
for the crimes charged, consistently maintaining that he had not
committed them and declining to participate in risk assessment
for sex offenses. The PSR also included a victim impact letter
from the children’s mother. She stated that Tucker’s crimes had
led to a deterioration of her relationships with her children and
behavior issues.
                               - 864 -
           Nebraska Supreme Court A dvance Sheets
                   301 Nebraska R eports
                         STATE v. TUCKER
                         Cite as 301 Neb. 856

   At the sentencing hearing, the district court stated that it had
considered the evidence at trial and the PSR in their entirety,
particularly Tucker’s pattern of criminal behavior and failure to
take responsibility for his actions or empathize with the victims
in this case. The district court noted that its sentencing took
into account the nature and circumstances of the crimes and
Tucker’s history, character, and condition.
   The district court sentenced Tucker to 30 to 50 years’
imprisonment for first degree sexual assault of a child and 10
to 20 years’ imprisonment for each of the two counts of incest,
with all sentences to be served consecutively.
   Tucker now appeals his convictions and sentences.
                 ASSIGNMENTS OF ERROR
   Tucker assigns, rephrased, (1) that the district court erred
in admitting unreliable Y-STR DNA evidence, causing undue
prejudice; (2) that the evidence was insufficient to prove the
crimes charged; and (3) that the district court abused its discre-
tion in imposing excessive sentences.
                   STANDARD OF REVIEW
   [1] An appellate court reviews for abuse of discretion a trial
court’s evidentiary rulings on relevance, whether the probative
value of evidence is substantially outweighed by the danger of
unfair prejudice, and the sufficiency of a party’s foundation for
admitting evidence. State v. Trotter, 299 Neb. 392, 908 N.W.2d
656 (2018).
   [2] The standard for reviewing the admissibility of expert
testimony is abuse of discretion. State v. Oliveira-Coutinho,
291 Neb. 294, 865 N.W.2d 740 (2015).
   [3] In reviewing a criminal conviction for a sufficiency of
the evidence claim, whether the evidence is direct, circum-
stantial, or a combination thereof, the standard is the same:
An appellate court does not resolve conflicts in the evidence,
pass on the credibility of witnesses, or reweigh the evidence;
such matters are for the finder of fact. The relevant question
for an appellate court is whether, after viewing the evidence in
                               - 865 -
           Nebraska Supreme Court A dvance Sheets
                   301 Nebraska R eports
                         STATE v. TUCKER
                         Cite as 301 Neb. 856

the light most favorable to the prosecution, any rational trier
of fact could have found the essential elements of the crime
beyond a reasonable doubt. State v. Wells, 300 Neb. 296, 912
N.W.2d 896 (2018).
   [4] An appellate court will not disturb a sentence imposed
within the statutory limits absent an abuse of discretion by
the trial court. State v. Ortega, 290 Neb. 172, 859 N.W.2d
305 (2015).
                            ANALYSIS
Admissibility of Y-STR DNA Evidence.
    Tucker challenges the admission of the Y-STR DNA testing
and any opinions derived from such testing. His brief contends
that the probative value of this evidence was outweighed by
its prejudicial effect because the evidence is unreliable. We
understand Tucker to be making two basic arguments against
the admissibility of the Y-STR DNA evidence. The primary
argument is a contention that the inherent nature of Y-STR
DNA evidence makes its admission unfairly prejudicial in any
case. The second challenges the reliability of the conclusions
regarding the Y-STR DNA evidence reached in this case. We
take up each of these contentions in turn.
    [5-9] We first address Tucker’s arguments that the Y-STR
DNA evidence was unfairly prejudicial. Evidence is relevant if
it tends in any degree to alter the probability of a material fact.
State v. Grant, 293 Neb. 163, 876 N.W.2d 639 (2016). Under
Neb. Evid. R. 403, Neb. Rev. Stat. § 27-403 (Reissue 2016),
relevant evidence may be excluded if its probative value is sub-
stantially outweighed by the danger of unfair prejudice. Grant,
supra. Most, if not all, evidence offered by a party is calculated
to be prejudicial to the opposing party. State v. Chauncey, 295
Neb. 453, 890 N.W.2d 453 (2017). Unfair prejudice means an
undue tendency to suggest a decision based on an improper
basis. Id. It speaks to the capacity of some concededly relevant
evidence to lure the fact finder into declaring guilt on a ground
different from proof specific to the offense charged, commonly
on an emotional basis. Id.
                              - 866 -
           Nebraska Supreme Court A dvance Sheets
                   301 Nebraska R eports
                        STATE v. TUCKER
                        Cite as 301 Neb. 856

   Tucker’s primary argument against the admission of the
Y-STR DNA evidence is that juries will inevitably base their
decision on an improper basis by incorrectly perceiving the
Y-STR DNA “match” testimony as conclusively connecting
the defendant to the sample. Tucker asserts that jurors are
inclined to think of any evidence of a DNA “match” of having
an extremely small probability of being the result of coinci-
dence. But, as he correctly points out, the Y-STR DNA testing
in this case led to a 1-in-1,842 chance of a coincidental match.
According to Tucker, this relatively greater chance of a random
match renders the evidence “completely unreliable.” Brief for
appellant at 37.
   We have previously recognized a risk that a jury might
give undue weight to DNA evidence if it is introduced with-
out proper context. See State v. Johnson, 290 Neb. 862, 862
N.W.2d 757 (2015). In Johnson, we observed that “‘[b]ecause
the potential precision of DNA testing is so well known, a
jury might assume that any DNA profile match is extremely
unlikely and therefore extremely probative’—even when this
is not true.” 290 Neb. at 883, 862 N.W.2d at 774, quoting
Peters v. State, 18 P.3d 1224 (Alaska App. 2001). We have
not, however, concluded that the appropriate measure to pre-
vent a jury from making such an assumption is the wholesale
exclusion of DNA evidence falling below a certain threshold
of precision. Rather, we have emphasized the need for evi-
dence of DNA testing to be accompanied by evidence of the
statistical significance of the findings if it is to be admitted.
Johnson, supra.
   In this case, Tucker cannot contend that the State sought to
introduce the Y-STR DNA evidence without the necessary sta-
tistical context. As we have noted, the State introduced much
evidence regarding the statistical context for the Y-STR DNA
evidence. The jury heard explanations of the relative probative
value of Y-STR DNA testing and autosomal DNA testing. Both
forensic scientists testified that males share the same Y-STR
DNA profile with other males in the same paternal lineage,
                              - 867 -
           Nebraska Supreme Court A dvance Sheets
                   301 Nebraska R eports
                        STATE v. TUCKER
                        Cite as 301 Neb. 856

as well as others in the general population. Their testimony
clearly illustrated that due to this recurrence, Y-STR DNA
testing results are not as probative as autosomal DNA test-
ing results. They both explained that Y-STR DNA statistical
analysis would not render coincidental random match prob-
abilities such as one in several hundred quintillions, showing a
particular profile is extremely rare in the population. Instead,
Bishop testified, Y-STR DNA testing might produce a random
match probability of one in a few thousand, as it did in this
case, where Y-STR DNA statistical analysis revealed a 1-in-
1,842 probability for African-American contributors that a ran-
dom Y-STR DNA profile unrelated to this case would match
the profile found on M.T.’s shorts. Because the Y-STR DNA
testing results were accompanied by the required statistical
context, its admission was consistent with the principles we set
forth in Johnson.
   Moreover, we do not believe that Y-STR DNA evidence is
so unique that something other than the principles of Johnson
should govern its admissibility. The probabilities of a coinci-
dental match may be exponentially greater with Y-STR DNA
evidence than with autosomal DNA evidence, but, if those
differences are explained to the jury, we see no reason why
jurors would be incapable of grasping the difference. We have
previously rejected claims that jurors would not be capable of
assigning appropriate weight to “the statistical analysis that
accompanies DNA evidence,” State v. Bauldwin, 283 Neb. 678,
703, 811 N.W.2d 267, 288 (2012), and reject any suggestion
that would be the case with Y-STR DNA evidence.
   Y-STR DNA evidence may be less probative than other
DNA evidence, but if we were to find it inherently prejudicial,
as Tucker urges, we would be treating such evidence differ-
ently from other types of evidence that have similar probative
value and that are introduced for the same purpose. As the
district court and other courts have observed, Y-STR DNA evi-
dence can be used in much the same manner as shoe imprint
evidence. Shoe imprint evidence is routinely admitted to show
                              - 868 -
           Nebraska Supreme Court A dvance Sheets
                   301 Nebraska R eports
                        STATE v. TUCKER
                        Cite as 301 Neb. 856

that an imprint at a crime scene matches shoes owned by a
defendant even though any number of individuals may own
shoes identical to the defendant’s.
      The coincidence that [a Y-STR DNA] profile matches that
      of defendant is probative of his guilt in the same man-
      ner as if he had owned shoes that matched a foot imprint
      found at the crime scene. It is up to the jury to weigh the
      probative value of that evidence in light of the fact that
      a significant number of other individuals may possess the
      same profile.
State v. Calleia, 414 N.J. Super. 125, 152, 997 A.2d 1051, 1066
(2010), reversed on other grounds 206 N.J. 274, 20 A.3d 402
(2011). See, also, People v. Stevey, 209 Cal. App. 4th 1400,
148 Cal. Rptr. 3d 1 (2012).
   Finally, we note that our conclusion that the Y-STR DNA
evidence introduced in this case was not unfairly prejudi-
cial is not a novel conclusion. Courts in a number of other
states have reached the same conclusion. See, e.g., State v.
Escalante-Orozco, 241 Ariz. 254, 386 P.3d 798 (2017), abro-
gated on other grounds, State v. Escalante, 245 Ariz. 135,
425 P.3d 1078 (2018) (Y-STR profile evidence is not mislead-
ing, nor is its probative value outweighed by risk of unfair
prejudice; jury is capable of understanding limited proba-
tive value of this evidence and giving it whatever weight it
deserves); State v. Jones, 345 P.3d 1195 (Utah 2015) (Y-STR
DNA evidence properly explained to jury such that risk of
unfair prejudice through confusing or misleading jury did not
substantially outweigh probative value of evidence); People
v. Wood, 307 Mich. App. 485, 862 N.W.2d 7 (2014), vacated
in part on other grounds 498 Mich. 914, 871 N.W.2d 154
(2015) (limitations of Y-STR DNA testing were presented
to jury such that there was no danger of confusion or other
unfair prejudice that would substantially outweigh proba-
tive value).
   Having rejected Tucker’s argument that Y-STR DNA evi-
dence is inherently unfairly prejudicial, we move to Tucker’s
                              - 869 -
           Nebraska Supreme Court A dvance Sheets
                   301 Nebraska R eports
                        STATE v. TUCKER
                        Cite as 301 Neb. 856

assertion that the testimony offered regarding the Y-STR DNA
evidence in this case was unreliable. Here, Tucker claims that
the database used by Bishop to arrive at her statistical conclu-
sions may not be representative of the population in a given
area and that therefore, there is a risk that Tucker’s Y-STR
DNA is even more common than Bishop acknowledged and
thus there is an even greater chance of a coincidental match.
This seems to be an attempt at a Daubert/Schafersman chal-
lenge, even though Tucker’s brief does not cite to Daubert/
Schafersman or address its framework. But even if we liberally
construed Tucker’s brief as having framed his argument as a
Daubert/Schafersman issue, the argument fails.
   Tucker’s argument is premised in part on contentions about
the U.S. Y-STR database made in articles published in 2003.
Bishop, however, testified at the Daubert/Schafersman hearing
that she was familiar with the articles Tucker relies upon. She
explained that she found these articles to be irrelevant, because
they were about very small sample sizes and Y-STR DNA sci-
ence has improved since their publication. In fact, she testified
that the U.S. Y-STR database upon which she relied was not
even established at the time the articles upon which Tucker
bases his challenge were written. The remaining article Tucker
cites to support this argument was not presented to the district
court and is not in the record before us for consideration. See
State v. Patton, 287 Neb. 899, 845 N.W.2d 572 (2014) (party’s
brief may not expand evidentiary record). Given Bishop’s tes-
timony concerning the articles Tucker offered to the district
court, we see no abuse of discretion in the admission of the
Y-STR DNA evidence.
   In sum, we conclude that the Y-STR DNA evidence in this
case did not suggest a decision based on an improper basis and
that thus, its prejudicial effect did not outweigh its probative
value. Moreover, Tucker’s Daubert/Schafersman arguments
also fail. Therefore, the district court did not abuse its discre-
tion in admitting such evidence at trial.
                              - 870 -
           Nebraska Supreme Court A dvance Sheets
                   301 Nebraska R eports
                        STATE v. TUCKER
                        Cite as 301 Neb. 856

Sufficiency of Evidence.
   We next address Tucker’s argument that the evidence was
not sufficient to support his convictions. The relevant ques-
tion when such a challenge is made is “whether, after viewing
the evidence in the light most favorable to the prosecution,
any rational trier of fact could have found the essential ele-
ments of the crime beyond a reasonable doubt.” State v.
McCurdy, ante p. 343, 351, 918 N.W.2d 292, 298 (2018).
Tucker, however, does not contend that there was no evidence
of the essential elements of either first degree sexual assault
of a child or incest. And, given the testimony at trial that
Tucker penetrated M.T.’s mouth with his penis when M.T.
was 11 years old and Tucker was 31 years old; that Tucker
performed cunnilingus on M.T.; that Tucker placed an electric
toothbrush on M.T.’s vagina; and that upon Tucker’s instruc-
tions, M.T. performed fellatio on E.T. and R.T., and E.T. and
R.T. performed cunnilingus on M.T., such an argument is not
available to him.
   Instead, Tucker argues that because the children “did not
testify to a cohesive story either individually or collectively,”
brief for appellant at 43, no rational juror could have found
Tucker guilty beyond a reasonable doubt. In other words,
Tucker is asking us to reweigh the evidence and find that the
testimony of the children was not credible. “But that is not the
role of an appellate court.” State v. Jones, 296 Neb. 494, 499,
894 N.W.2d 303, 307 (2017).
   [10] The credibility and weight of witness testimony are
for the jury to determine, and witness credibility is not to be
reassessed on appellate review. State v. Archie, 273 Neb. 612,
733 N.W.2d 513 (2007). Our task is limited to determining
whether, after viewing the evidence in the light most favorable
to the prosecution, any rational trier of fact could have found
beyond a reasonable doubt that Tucker committed the charged
offenses. See id. Based on the evidence summarized above,
we conclude it could.
                              - 871 -
           Nebraska Supreme Court A dvance Sheets
                   301 Nebraska R eports
                        STATE v. TUCKER
                        Cite as 301 Neb. 856

Excessive Sentences.
   Finally, we address Tucker’s claim that he received exces-
sive sentences. Tucker does not dispute that the sentences
imposed were within statutory limits. Rather, he argues only
that the district court did not meaningfully consider his child-
hood trauma, mental condition, and need for rehabilitation. We
conclude that the district court did not abuse its discretion in
sentencing Tucker.
   [11-14] Where a sentence imposed within the statutory
limits is alleged on appeal to be excessive, the appellate court
must determine whether a sentencing court abused its discre-
tion in considering and applying the relevant factors as well as
any applicable legal principles in determining the sentence to
be imposed. State v. Russell, 299 Neb. 483, 908 N.W.2d 669
(2018). Relevant factors customarily considered and applied
are the defendant’s (1) age, (2) mentality, (3) education and
experience, (4) social and cultural background, (5) past crimi-
nal record or record of law-abiding conduct, and (6) motiva-
tion for the offense, as well as (7) the nature of the offense
and (8) the amount of violence involved in the commission of
the crime. Id. The appropriateness of a sentence is necessar-
ily a subjective judgment and includes the sentencing judge’s
observation of the defendant’s demeanor and attitude and all
the facts and circumstances surrounding the defendant’s life.
State v. Steele, 300 Neb. 617, 915 N.W.2d 560 (2018). And
generally, it is within a trial court’s discretion to direct that
sentences imposed for separate crimes be served either concur-
rently or consecutively. State v. Leahy, ante p. 228, 917 N.W.2d
895 (2018).
   Our review of the record demonstrates that the district court
properly considered and applied the necessary sentencing fac-
tors. The PSR shows that Tucker exhibited mental illness after
having grown up in an environment of poverty, crime, drug
use, instability, and trauma. Certainly, these disadvantages
were relevant to the sentencing calculus, but the district court
stated that it considered the PSR in its entirety, and we have
                               - 872 -
           Nebraska Supreme Court A dvance Sheets
                   301 Nebraska R eports
                         STATE v. TUCKER
                         Cite as 301 Neb. 856

no reason to believe the district court did not weigh those dis-
advantages against other factors. Those other factors, however,
would include Tucker’s significant pattern of criminal behav-
ior and the nature of the offenses at issue. On this point, the
record shows that Tucker’s crimes against the children in this
case were particularly serious. Tucker used games and candy to
systematically lure children in his care into participating in acts
that will have a lasting negative impact on their lives. And as
the district court emphasized, Tucker has not taken responsibil-
ity for his actions.
   Having reviewed the record and the district court’s remarks
in light of the familiar sentencing factors set forth above, we
conclude that the district court did not abuse its discretion in
sentencing Tucker within statutory limits.
                       CONCLUSION
   We conclude that the district court did not abuse its discre-
tion in admitting Y-STR DNA evidence at trial. We further
determine that the evidence presented at trial was sufficient
to support Tucker’s convictions and that the district court
did not abuse its discretion in sentencing him. Consequently,
we affirm.
                                                    A ffirmed.
   Miller-Lerman, J., not participating.
