Field 04 of 05 · Ancestry and paternity
NSW Health CGE · last updated March 2021
Ancestry and paternity tests
An ancestry test looks for clues about where your ancestors might have come from and about relationships in families, says NSW Health’s Centre for Genetics Education (CGE), on a page last updated in March 2021. Paternity tests are sold by mail order and online, it says, but the Family Court will consider DNA profiling results only if a laboratory approved for paternity testing did the test.
General information, not medical advice. Call Triple Zero (000) in an emergency, or go to the emergency department of your nearest hospital. The official place to check is NSW Health’s Centre for Genetics Education.
Method
Ancestry testing methods
CGE’s page says DNA testing has recently become popular with people looking for clues to where their ancestors came from and to family relationships. It says genetic ancestry testing looks at the level and type of genetic relationship between people, and that ancestry testing is commonly offered online, through private companies.
The method, in CGE’s description: like other DNA testing, it analyses repeated DNA sequences, or large numbers of variations across the whole genome, and compares them with databases to look for similarities. For autosomal DNA testing, which looks at large numbers of variations across a person’s whole genome, the results are compared with those of other people who have taken the tests, to give an estimate of a person’s ethnic background.
CGE describes ancestry testing as ending in a comparison with databases, which is why the database behind a result matters, as the limits below show.
Test kinds
Kinds of ancestry test
CGE’s page lists three kinds of genetic ancestry testing that may be used: Y chromosome testing, mitochondrial DNA testing and autosomal DNA testing. Y chromosome testing can only be done on males, because females do not have a Y chromosome. Mitochondrial DNA is passed on only by the mother, so it does not track through the male line.
It says it helps to know what type of testing is being arranged for ancestry, to make sure it will answer the questions being asked.
CGE says autosomal results may show some variation between members of the same family.
Limits
Limits of ancestry testing
CGE says ancestry testing has a number of limitations. Among those it names:
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Different databases
Because different companies compare test results with different databases, ethnicity results may not be consistent.
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Mixed populations
Findings about ethnicity may differ from what a person expects, because people have mixed with different populations throughout history, so any of us may carry many different variations in our DNA.
These are the limits as CGE described them in March 2021. Its page is the place to read them in full.
Paternity
Paternity tests and the Family Court
CGE says paternity tests are available commercially, by mail order and through the internet. It goes on to list issues for consideration that these tests raise; CGE’s page on forensic, paternity and ancestry testing has that list.
The page also says the Family Court will consider the results of DNA profiling only if they come from a laboratory approved for paternity testing.
Personal information
Ancestry results as personal information
An ancestry result is genetic information about you. In the OAIC’s privacy guidelines, genetic information that is not health information is sensitive information, which generally gets a higher level of privacy protection than other personal information. Your genetic data and privacy sets out that guidance.
Health questions
Ancestry tests and health questions
For a question about health rather than heritage, healthdirect says it is best to see your doctor or a genetic counsellor if you are thinking about having a test. What a genetic test result can and cannot tell you looks at what any result can show.