New Mexico

Department of Public Safety

Keeping New Mexico Safer Through Safe Roads and Safer Communities

Biology Unit: Serology / DNA

The Biology unit analyzes biological fluids and materials submitted as evidence from crimes committed throughout the state of New Mexico. Typical crimes encountered include, but are not limited to, property crimes, sexual assaults, homicides, and other violent crimes.

Unit Accreditation

The Biology unit, in addition to the ASCLD/LAB accreditation of the forensic laboratory, maintains accreditation under the FBI’s Quality Assurance Standard for DNA Testing Laboratories. The section has been conducting forensic serology / DNA analysis since 1993.

Combined DNA Index System (CODIS)

DNA analysts compare a DNA profile generated from an item of evidence to a DNA profile from a known individual. In cases in which there is no known perpetrator, the evidentiary DNA profile may be searched in CODIS (Combined DNA Index System). CODIS is the FBI’s national DNA database, which houses DNA profiles generated from crime scene samples, arrestees, and convicted offenders, among others. CODIS blends forensic science and computer technology into an effective tool for solving crimes by enabling federal, state, and local laboratories to exchange and compare DNA profiles electronically, thereby linking crimes to each other and to arrestee/convicted offenders.

Processing Methods

Utilizing state-of-the-art technology and forensic serological techniques, perpetrators and other individuals are routinely identified from minute amounts of human biological material. Types of services provided by the NMDPS Biology section include autosomal STR testing (traditional DNA analysis), male Y-STR DNA testing, criminal paternity, and cold cases. Analysts are tasked with identifying the biological fluid present on an item of evidence (blood, semen, or saliva) and determining who is or is not the source of the fluid. An increasing trend in investigations is the utilization of “touch DNA” testing for crimes without biological fluid evidence.

Helpful Hints

  • Before items of biological evidence can be submitted to the laboratory for testing, agencies must first obtain a DNA acceptance code by discussing the specifics of the case with a DNA analyst. Only items of evidence listed on the DNA acceptance code will be accepted for submission.
  • Types of items not accepted by the laboratory include liquid body fluids and syringes containing needles.

Biology/DNA Unit Frequently Asked Questions:

Why do I need a DNA acceptance code?
The purpose of discussing the specifics of a case with a DNA analyst is to limit the submitted items to the most probative pieces of evidence – this helps minimize backlog DNA cases and helps to decrease your case’s turnaround time. It also allows the DNA analyst to determine CODIS eligibility. If during the first round of testing nothing of value is generated, you can request to submit more items of evidence for additional testing.
When is a DNA acceptance code required?
A DNA acceptance code is required with all new case submissions. A new DNA acceptance code is required for all additional evidence submissions, with the only exception being the submission of known DNA standards.
How should biological evidence be packaged?
Biological evidence should be completely dry before packaging. The evidence should be packaged in paper only, NEVER plastic. Biological evidence should be stored in a cool place (room temperature) and should be protected from humidity and heat.
What kind of items will not be accepted for DNA testing?
  • Liquid biological fluids (blood, urine, etc.)
  • Syringes with needles
  • Fired or unfired casings or cartridges for touch DNA
What types and how many items can I submit for different types of crimes?
Violent crimes (Homicides, assaults, sexual assaults, etc.) * There is no limit on the number of items allowed to be submitted in violent crimes. All items, with the exception to the items listed above, may be accepted on a case by case basis. We do ask that the items be limited to the most probative items first. Additional submissions may be considered at a later date. * Although they are not required for case submission, it is strongly recommended that all DNA standards from relevant individuals be submitted with the first round of testing (victims and suspects). Non-violent/Property crimes * You can submit a maximum of two items of evidence for the first submission. Any DNA standards collected do not count toward this number. * Items left behind by the suspect may be submitted for touch DNA testing. No touch DNA swabs or items belonging to the victim will be accepted (door knob swabs, drawer handle swabs, etc.). * In stolen vehicle cases, a steering wheel swab may be submitted if the DNA standard from the owner of the vehicle is also submitted. No other touch DNA swabs from the vehicle will be accepted, but items left behind by the suspect will be accepted. * The best type of evidence in this type of case are items such as cigarette butts, blood, drinking containers, clothing left behind, etc. No DNA standard from the victim is required with this type of evidence. * Items for touch DNA testing will not be worked by both the Latent Prints and DNA sections. Please contact a forensic scientist to determine what discipline will provide the best chance of getting helpful results. Felon in Possession of a Firearm/Drug Possession cases * Will not be accepted if the item(s) were taken directly from the suspect’s person. * You must choose either Latent Prints or DNA on specific items. It’s OK if you have items for both disciplines, but a single item will not be accepted for both types of testing. * A DNA standard from the suspect is required to be submitted with the evidence for DNA testing.
I have Backlog Sexual Assault Evidence kits. What should I do with them?
Submit them! The DNA section is diligently working to clear our state of sexual assault kits that have never been worked. Please contact the DNA section supervisor for instructions for submission.
What if my suspect is “in the system” (CODIS), do I still have to collect a standard from him/her?
Yes. The CODIS database does not contain personally identifiable information. DNA analysts do not have the ability to search the CODIS database for DNA profiles of specific individuals. DNA standards from arrestees/convicted offenders do not maintain a chain of custody and can therefore not be used as evidence in court. A separate DNA standard from the suspect in most cases will be required. A suspect standard that is submitted upon the initial submission of the evidence will make the entire process more efficient and will even facilitate things down the line if a CODIS “hit” occurs at a later time.
What do I do once I get notification of a CODIS hit?
You will need to collect a DNA standard from the person identified through the CODIS hit and submit that to the laboratory for direct comparison to the evidentiary profile. Per New Mexico legal statutes, offender and arrestee samples in CODIS are for data basing purposes only and are not to be used as standards for comparison. A CODIS “hit” is strictly an investigative lead and is not appropriate for use in court.
Can all DNA profiles be entered/searched in CODIS?
No. The FBI has several rules that govern the entry of DNA profiles into CODIS. Victim DNA profiles cannot be entered into CODIS. Only evidentiary DNA profiles generated from the commission of a crime can be entered into CODIS. DNA profiles generated from items collected from a suspect’s person/property cannot be entered into CODIS (which is why a standard must be submitted for a felon in possession of a firearm case). For more information, visit the NDIS procedures at http://www.fbi.gov/about-us/lab/biometric-analysis/codis/codis-and-ndis-fact-sheet
When should I collect DNA standard (s) from the person(s) of interest in a case?
All the time, if possible. It is easier to collect a standard during investigation of a case than at a later date. In cases where a search warrant is required, or there is no suspect, then those cases can be submitted as is.
Why do I have to submit elimination standards?
DNA results can be very difficult to interpret without a standard for comparison. If an item is collected from a person’s home/car, it is expected to find their DNA on those items. Analysts are not allowed to enter victim DNA profiles into CODIS, so the owner(s) should be eliminated from the evidence before the evidentiary profile can be entered into CODIS.
Does your laboratory do any specialized testing?
Yes. We perform male Y-STR DNA testing, criminal paternity testing, and reverse parentage testing. For male Y-STR testing, a male DNA standard is required. For criminal paternity testing, standards from the alleged father, the biological mother, and the child/product of conception are required. For reverse parentage testing, standards from the biological mother, biological father, and alleged child are required. No other specialized testing (such as mitochondrial DNA testing or animal DNA testing is currently offered at this facility).
What is male Y-STR DNA testing?
Male Y-STR DNA testing uses the same technology as conventional DNA testing, however, it only tests the Y chromosome. The Y chromosome is passed unchanged, baring mutation, from father to son, so an entire paternal male lineage may have the same male Y-STR DNA profile. Since this type of testing targets only the male DNA present in a sample, it can be useful in cases where there is too much female DNA present, as in sexual assault cases.
What is a DNA mixture?
A DNA mixture is when more than one person contributes their DNA to an item of evidence. An analyst can sometimes separate out the components of a mixture, as in who deposited the most amount of DNA (major DNA profile) and who deposited the least amount of DNA to a sample (minor DNA profile). If the components of a mixture cannot be separated out, it is simply reported as a mixture.
What is a “foreign” DNA profile?
When swabs are collected from a person’s body, it is expected to find their DNA profile from those swabs. When there is DNA present on those body swabs that does not belong to that person, it is called “foreign” DNA.