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
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