United States Court of Appeals
                            FOR THE EIGHTH CIRCUIT



                                    No. 00-4005



United States of America,                *
                                         *
      Plaintiff/Appellee,
                                         *
      v.                                 *         Appeal from the United States
                                         *         District Court for the Southern
Bradley Wayne Boswell,                             District of Iowa.
                                         *
                                         *
      Defendant/Appellant.
                                         *



                             Submitted: May 15, 2001
                                 Filed: October 16, 2001


Before WOLLMAN, Chief Judge, HANSEN, Circuit Judge, and SCHREIER,1
District Judge.


SCHREIER, District Judge.

       Dr. Bradley Wayne Boswell appeals his conviction on two counts of making
false statements to the government. Dr. Boswell raises three issues on appeal. First,


      1
       The Honorable Karen E. Schreier, United States District Judge for the
District of South Dakota, sitting by designation.
that the district court2 erred in admitting evidence of DNA test results involving the
comparison of swine serum samples. Second, that the evidence was insufficient to
support the conviction on grounds he falsified the number of swine he claimed to
have bled. Third, that Dr. Boswell was denied due process because the refrigerated
serum samples deteriorated while kept in storage. We affirm.

      Pseudorabies is a contagious air-transmitted disease that causes respiratory and
reproductive problems in swine. The Pseudorabies Eradication Program is a joint
federal, state, and swine industry project designed to eradicate the disease. The
program pays veterinarians on a “fee-basis” to collect blood samples from swine on
Iowa farms and submit the samples to the Iowa State University Diagnostic
Laboratory. The veterinarians receive $20 for each farm visit and $4.50 per animal
from which a blood sample is drawn.

       Dr. Bradley Boswell was a licensed veterinarian at the time of the events in
question. Dr. Boswell’s license was reinstated after it had been revoked by the Iowa
Board of Veterinarian Medicine in 1991, for submitting falsified test records, failing
to properly supervise employees, and violating food and drug regulations regarding
use of illegal animal drugs.

       Dr. Boswell agreed to work with the Animal Plant Health Inspection Service
(APHIS) as a “Fee Veterinarian” under the Pseudorabies Control Agreement.
Dr. Alison King, a field veterinarian employed by APHIS, asked Dr. Boswell in early
1998 to obtain serum samples from pigs on Thad Benskin’s farm. Dr. Boswell claims
he bled some of the samples in February of 1998 with the assistance of Thad Benskin,
and later returned to the farm and bled the rest of the animals with the help of his
friend Bart Elder. In total, Dr. Boswell submitted one hundred and twenty samples


      2
       The Honorable Harold D. Vietor, United States District Judge for the
Southern District of Iowa.

                                         -2-
from the Benskin farm to the ISU laboratory. Some of the blood serum samples
tested positive for psuedorabies.

      Dr. Boswell was surprised to learn that some of the samples had tested positive
for pseudorabies. He then resubmitted allegedly identical samples to the ISU
laboratory, claiming that he used the serum kept on reserve from the prior month’s
bleeding. All of the resubmissions came back negative. Dr. Boswell also claims he
decided to re-bleed and re-submit sixty samples from the Benskin farm. New samples
arrived at the ISU lab on March 10 which also tested negative.

       Dr. King was suspicious that test results from the same animal could move
from positive to negative. Based on this suspicion, King and a group of federal
veterinarians re-tested some of the swine on the Benskin farm. The federal
investigators drew blood from a random sample of thirty sows and approximately 40
percent of the thirty sows tested positive for pseudorabies.

      Dr. King then sent Dr. Boswell’s original and resubmitted samples to the
National Veterinarian Service Laboratory (NVSL). A lab technician at NVSL
concluded that the original and resubmitted samples appeared to be adulterated.
NVSL was also skeptical of Dr. Boswell’s assertions that the sets of samples he
submitted were from the same animal. NVSL sent some of the two sets of samples
to Stormont Laboratories for additional testing. Stormont tested the DNA of
Dr. Boswell’s submissions by using a process called polymerase chain reaction
(PCR). Stormont concluded that the paired samples were not from the same animals.

       Dr. Boswell was charged by indictment with nine counts of making false
statements and two counts of witness tampering. Count Two was dismissed at the
government's request prior to trial. The district court entered a judgment of acquittal
on the two counts of tampering with a witness and the jury acquitted Dr. Boswell of
six counts of making a false statement. The jury convicted Dr. Boswell on two counts

                                         -3-
of making false statements in violation of 18 U.S.C. § 1001 (Counts Four and Five).
These two counts of conviction involved separate written representations
Dr. Boswell made on separate official government Pseudorabies Serology Forms with
respect to the Benskin swine herd. Count Four charged that Dr. Boswell's written
statement on the February 1998 form that he had obtained the 120 blood samples
from the Benskin herd in February 1998 was false because Dr. Boswell "well knew
that he had bled less (sic) than 120 swine." Count Five charged that the form
submitted in March 1998, with the thirty blood samples from serum that Dr. Boswell
claimed were from the same hogs bled at the Benskin farm in February 1998, was
false because he then "well knew these [thirty] specimens were not from the same
swine, and that he had not submitted specimens in accordance with federal and state
regulations and instructions issued by the Veterinarian-in-Charge."

                                           I.

       Dr. Boswell contends the district court abused its discretion by admitting into
evidence DNA test results taken from swine serum samples Dr. Boswell submitted
to ISU laboratories. A district court’s admission of DNA evidence is reviewed under
an abuse of discretion standard. See United States v. Beasley, 

, 1445
(8th Cir. 1996), cert. denied, 

(1996). This court must determine
whether or not the district court made a clear error of judgment in weighing the facts
on the basis of the record before it. See United States v. Bahema, 

, 809
(8th Cir. 2000).

       The admission of scientific expert testimony is dependent upon the court’s
determination that the proposed testimony constitutes (1) scientific knowledge that
(2) will assist the trier of fact to understand or determine a fact in issue. See Daubert
v. Merrell Dow Pharmaceuticals, Inc., 

, 

, 

(1993). The district court serves as a “gatekeeper” for the admission of novel
scientific evidence. See United States v. Martinez, 

, 1196 (8th Cir. 1993).

                                          -4-
The district court must conduct a preliminary assessment of whether the reasoning or
methodology underlying the testimony is scientifically valid and whether that
reasoning can be applied to the facts at issue. See 

, 113 S.
Ct. at 2796. The factors the district court may consider include: (1) whether a theory
or technique can be (and has been) tested; (2) whether the theory or technique has
been subjected to peer review and publication; (3) the known or potential rate of
error; and (4) whether the technique is generally accepted. 

113 S. Ct.
at 2795-96.

      There is sufficient evidence that the district court was justified in permitting
the admission of PCR test results of the swine DNA. First, the PCR process is
approximately ten years old and it has undergone extensive testing. See United States
v. Gaines, 

, 1435 (S.D. Fla. 1997). Numerous courts have
recognized the multitude of scientific articles endorsing the use of PCR analysis for
forensic purposes. See 

This court previously found PCR testing to be an
accurate method of analysis when a protocol that conforms to guidelines accepted by
members of the forensic community are followed and controls are employed. See

. While the Beasley analysis applied to PCR testing of
human DNA, there is no evidence the district judge erred by extending the same
analysis to PCR testing of swine blood. In fact, Michael Spencer, a scientist with a
biotechnology company called Celera Aggen, testified that the method of PCR testing
on swine DNA is an acceptable and recognized test in the DNA testing community.

      Dr. Boswell asserts that Michael Spencer’s “backhand (and incompetent)
testimony” regarding the PCR method of DNA testing and the protocol at Stormont
did not lay sufficient foundation for the admission of the lab results. The record does
not support Dr. Boswell’s characterization of Mr. Spencer’s testimony. Mr. Spencer
is a biochemist from the University of California, at Davis. After graduation
Mr. Spencer was employed by the University of California, at Davis, in the
department of biological chemistry at the School of Medicine. Mr. Spencer was later

                                         -5-
employed at Stormont from 1992 until 1998 and was involved solely in animal DNA
testing.

       Dr. Boswell also contends that even if the PCR method of DNA testing on
swine blood is accepted in general, the results would still be inadmissible in this case
because no protocol was followed. This assertion is not supported by the record.
Although no written protocol for the analysis of swine blood at Stormont was
introduced, Mr. Spencer did describe the method and procedures used to do the PCR
analysis and, as mentioned above, verified that the procedure was an accepted one
among DNA experts. Mr. Spencer testified that he performed the DNA tests on the
blood samples submitted by Dr. Boswell and he detailed the reacting components he
used in the process. Mr. Spencer also stated that the methodology he used is like a
recipe where the amount of an ingredient may be varied, but the testing methodology
has the same basic components. Dr. Boswell further argues that the test was not
reliable given the condition of the samples. This assertion is contradicted by Mr.
Spencer who stated that the samples were delivered in a sealed container by express
courier and were then stored in a secure laboratory refrigerator.

       This court previously held that any alleged deficiencies must so alter the PCR
methodology as to make the test results inadmissable. See 

.
Dr. Boswell failed to prove that there were significant deficiencies in the protocol and
procedure used by Stormont Laboratories. Consequently, the alleged deficiencies go
to the weight to be given the DNA evidence, not its admissibility. See id.; United
States v. Johnson, 

, 953 (8th Cir. 1995). We, therefore, conclude that the
district court did not abuse its discretion in admitting the government’s DNA
evidence.




                                          -6-
                                          II.

       Dr. Boswell claims there was insufficient evidence for a reasonable jury to
have found that he falsified Pseudorabies Serology Forms by overstating the number
of animals he bled. This court examines the evidence in the light most favorable to
the government and provides the government with the benefit of all reasonable
inferences. See United States v. Wilson, 

, 409 (8th Cir. 1995). The jury’s
verdict must be upheld if any interpretation of the evidence allows a reasonable jury
to find guilt beyond a reasonable doubt. See United States v. Easley, 

, 67
(8th Cir. 1995).

       Count Four of the indictment alleges that Dr. Boswell falsified the number of
swine he claims to have bled at the Benskin farm. Dr. Boswell asserts that viewed
in the light most favorable to the government, it must be concluded that Dr. Boswell
bled forty-sixty pigs with Thad Benskin and later returned to the Benskin farm and
bled “a lot” of pigs with Bart Elder. Dr. Boswell contends that based on this premise
a reasonable jury could not have found a calculation that he bled 120 pigs was an
overstatement. The court disagrees. First, there is evidence in the record that
Mr. Elder never stepped foot on the Benskin farm, let alone bled pigs there. Second,
even if this court were to accept this premise of Dr. Boswell, the conclusion that a
reasonable jury must equate “a lot of pigs” with sixty to eighty pigs is wrong. We,
therefore, conclude a reasonable jury could have determined that Dr. Boswell did not
return to the Benskin farm with Mr. Elder, or that if he did visit the farm, he did not
bleed sixty to eighty pigs.

      Dr. Boswell’s next assertion is that no reasonable jury could have reached the
conclusion that when he submitted the serology form for the thirty samples of the
resubmission, he knew they were not a resubmission of the thirty prior samples from
the Benskin farm, as was alleged in Count Five. The first thirty samples that
Dr. Boswell submitted were received by ISU laboratory on February 21, 1998, and

                                         -7-
the second set of thirty samples were received on March 3, 1998. Dr. Boswell
contends the samples were from the same swine and the same bleeding.
Dr. Boswell’s assertion is contradicted by the scientists who received the submitted
and resubmitted samples. The DNA tests conducted by Stormont provided evidence
that the samples originally submitted by Dr. Boswell were not from the same animals
as the second submission. We, therefore, conclude that a reasonable jury could have
determined Dr. Boswell falsified the submissions.

                                           III.

       Dr. Boswell contends that Counts Four and Five should have been dismissed
because the government knowingly allowed the swine serum samples to degrade. We
defer to the district court’s factual findings with regard to the destruction of evidence.
See United States v. Clark, 

(8th Cir. 1992). A clearly erroneous
standard of review must be applied to the district court’s determination that the
government acted in good faith. See United States v. Ramos, 

, 67 (3d Cir.
1994); United States v. Bohl, 

, 909 (10th Cir. 1994).

        Dr. Boswell asserts that the government exhibited bad faith by knowingly
allowing the swine serum samples to deteriorate. This presumption is contradicted
by the affidavit of Dr. Boswell’s expert witness, Dr. Christopher Chase. Dr. Chase
states that: “In order for the samples of blood or serum to remain in a condition which
would accurately reflect the sample was in the same in vivo condition from the
animal, the samples must remain either refrigerated or frozen.” The samples in
question were preserved in such a manner for testing according to the policies of ISU
laboratories and NVSL personnel, and despite these efforts the samples deteriorated
naturally over the course of time.

      The Due Process Clause of the Fourteenth Amendment does not require that
law enforcement agencies preserve samples in order to introduce the results at trial.

                                           -8-
See California v. Trombetta, 

, 491, 

, 

(1984). Unless the defendant can show bad faith on the part of law enforcement,
“failure to preserve potentially useful evidence does not constitute a denial of due
process of law.” Arizona v. Youngblood, 

, 58, 

, 337, 

(1988). Dr. Boswell had the opportunity to raise the issue of the
evaporated serum at trial and to impeach the reliability of the test results, and
therefore had the opportunity to raise doubts in the mind of the jury. Furthermore, the
immediate case is distinguishable from the case cited by Dr. Boswell, United States
v. Bohl, 

(10th Cir. 1994). The government intentionally destroyed
evidence in Bohl. There is no record of that occurring in this case. We conclude that
Dr. Boswell was not deprived of his due process rights by the degradation of the
swine samples.

      The judgment is affirmed.

      A true copy.

             ATTEST:

                     CLERK, U.S. COURT OF APPEALS, EIGHTH CIRCUIT.




                                         -9-