Skip to content
 pdf

Considerations in Using Genetic Testing for Tribal Enrollment

By Jessica Bardill (Cherokee), Ph.D.

The collection of information for genetics research is different from the use of genetic testing in tribal enrollment. However, because many tribal leaders have requested information about genetic testing and tribal enrollment, this brief handout was developed. It is important to note that there is no genetic test that can prove an individual is from a specific tribe, or even that he or she is American Indian/Alaska Native (AI/AN). There are no genes that are known to be specific to tribes or AI/AN peoples. There are different kinds of genetic tests. Some tests, such as those that look at paternity or grandparentage, can be useful because they can evaluate possible biological relationships between an individual and current tribal members. Other kinds of genetic tests, such as genetic ancestry testing, are less useful because they provide much less specific information about relatedness between individuals.

Probability

In most all genetic testing, information is expressed in terms of probability or a chance of something happening. For example, genetic testing can estimate the chance of two individuals being related, or sometimes the probability of developing a certain disease[1].  Commonly this probability or chance is expressed as a percentage of how likely something is (99.5% for example). For parentage of a child, genetic testing can provide a very accurate probability estimate. In trying to determine whether a child is related to others (grandparents, siblings, cousins, aunts and uncles), the probability estimate will be less accurate due to a smaller amount of shared genetic markers between the child and more distant relatives. However, when distant relatives are tested, the results indicating the likelihood of relatedness can be more accurate when multiple individuals are tested. Generally, genetic testing of possible relationships with previous generations (e.g., parents, grandparents) is more reliable than genetic testing  that involves extended relatives in a person’s own generation or later generations (e.g., cousins).

Parentage, Grandparentage, and Siblingship Tests

DNA fingerprinting compares two genetic samples and determines the probability that the individuals are closely related. Types of DNA fingerprinting tests include:         

Maternity Testing – This kind of testing is only useful when the mother of the child is not known or confirmed through other documentation (hospital records, birth certificate, adoption papers), and should be used only to supplement the information available from other sources.  Having the mother tested as comparison with the child for paternity and other tests is common, but it should still be considered supplementary information.

Paternity Testing – This kind of testing is useful when the father of the child is not known.  It should be noted that in the general global population, non-paternity (where the man believed to be the father is not the father of a given child) in the population has been estimated to be at 10%[2]. This test can definitively determine who is not the father, and can identify with a slightly less than 100% confidence who is the father.

Grandparentage Testing – This testing is being marketed more and more to tribal communities and their members, and it helps in the case of a parent being unavailable for testing. This testing would be most useful on the paternal side given the other documentation of the mother and the birth, if paternity needs to be confirmed.  Certainty with this test is increased if both paternal grandparents can be tested to compare their genetic contributions with that of the child and mother to determine likelihood of relatedness.

Siblingship Testing – This testing has limited utility because siblings may receive different genetic contributions from their parents; however, this testing can be supplemented with mitochondrial and Y-chromosome testing in the analysis to establish connections between possible siblings and confirm parentage.

Extended Family Testing – This testing is minimally useful for understanding a child’s relatedness to a family. The best way to increase its reliably is to have as many family members tested within the direct lines as possible.

Genetic Ancestry Testing – This testing can be useful to supplement other information, such as siblingship testing or extending family testing, by following the mitochondrial or Y-chromosome DNA up a family line.  There are limited relations that can be established through this type of testing however (mother’s mother and maternal female relatives; father’s father and paternal male relatives), although the relatedness on those would be very certain.

Working with Labs

What to look for in a genetic testing lab

Accreditation from a national organization, such as the AABB (American Association of Blood Banks), and CLIA (Clinical Laboratory Improvement Amendments) certification (http://ghr.nlm.nih.gov/handbook/testing?show=all).  These qualifications indicate a commitment to quality assurance and government standards.

What to require in working with a genetic testing lab:

  • Written contracts
  • Sample return or agreements for the acceptable and not acceptable uses of samples
  • Confidentiality and Security of Information/Data
  • Informed Consent
  • Interpretation of Results/Data

Other Considerations:

This guide provides questions to help in determining what lab might be most appropriate for the work that the tribe wants to have done: http://www.dnacenter.com/native-american/choosing-a-dna-lab.html. This guide was developed by a genetic testing company, which is not endorsed by NCAI.

Additional Information

For a larger discussion of these concerns and more resources on genetic testing and tribal enrollment, please see the paper Tribal Enrollment and Genetic Testing.



[1] In some cases, a genetic test can conclusively say that if an individual has a specific  gene(s), they will develop a disease (e.g., Huntington’s Disease). Other genetic tests can indicate if an individual is more likely to develop a chronic disease (e.g., diabetes or heart disease).

[2] This figure has been debated and varies across cultural groups, but it is worth noting that many may not know their offspring are not theirs, and that many still maintain claims to kinship despite genetic evidence against it. http://www.anth.uconn.edu/degree_programs/ecolevo/kermyt.pdf

How Do We Decide?

A Guide for American Indian/Alaska Native Communities

The interactive decision guides provide a set of interactive questions to help you reflect on your feelings regarding research. Read More