DNA-based Genealogy Test May Reveal Infertility

Men who delve into their family history by having their DNA analyzed may find more information than they expected. They may find out that they are infertile.

According to NewScientist.com, many companies offering genealogical testing screen male customers' DNA for a region of the Y chromosome called DYS464 that happens to be linked with infertility. If it is missing, it's odds-on that the customer is infertile.

Companies should either stop looking at DYS464 or warn customers beforehand that it could reveal infertility, says Mark Jobling of the University of Leicester, UK. "I think it's daft to type DYS464," he says. "People are buying a genealogy test but end up getting a fertility test." A study by Jobling's team suggests that 1 in 1000 men has the deletion (Journal of Medical Genetics, vol. 42, p 366).

A man may believe that he is the father of his children, only to find out after a genetic test the unwelcome information that he is unlikely to be the biological father.

Comments

[walt]

Do not search DNA if you are not searching for the truth.

[Ann Turner]

I disagree with Jobling's conclusion. It would be a shame to "throw the baby out with the bath water," for DYS464 is a very informative marker. It typically has four copies on the Y chromosome, which yields a large number of possible combinations. (It's sometimes difficult to decide if two people actually match, since the four copies can't be distinguished, but that's another story.) You can see a list of observed haplotypes (set of results) at the Sorenson Molecular Genealogy Foundation website:

http://www.smgf.org/ychromosome/marker_details.jspx?marker=DYS464

The prevalence of the missing DYS464 reported by Jobling doesn't seem to hold for the genealogical testing companies. Bennett Greenspan, of Family Tree DNA, has encountered only a handful of cases (a prevalence of about one in 8,000), and he has personally contacted them. He says the news "did not come as a surprise" to any of them. Of course, people in a genealogical database may not be representative of the general population -- many people engage in genealogy to leave a legacy for their children, which means they have already demonstrated their fertility -- but this is not a huge problem.

Ann Turner
co-author (with Megan Smolenyak) of "Trace Your Roots with DNA"

[Jim Liddil]

You can read the actual article here:

http://jmg.bmj.com/cgi/reprint/42/4/366

Also note this was from 2005 and the data may have changed. I'll probably do a Pubmed search on this. I have access to the full article text via my employer

[Charles Ellis]

If someone is seeking genealogical information, why would they not want to know the whole truth. Lack of the DYS484 chromosone is just another piece of information. Some people are always trying to hide the truth. It follows the same lame excuses that some scholars attempt to rewrite our history books to fit their agenda.

[Virginia Lapham]

The issues here seem to be those of informed consent and right to know/not know. Do the companies notify would-be DNA donors that the labs will be testing for fertility/infertility and if so, do they give customers an option of being informed or not? Genealogy-genetic testing would seem no different than other genetic testing where informed consent and the right to know or not know are important ethical considerations and people with questions or concerns may be referred for genetic counseling prior to testing.

[Dino (All Dino, All the Time)]

So let's see. The Y chromosone gets passed on in such a way that we can use it to test for parentage.

If DYS484 is missing, chances are that you're infertile.

So how do you pass this condition on? I had always assumed that infertility was not a heriditary condition.

[Ann Turner]

Dino, the mutation that causes a deletion of the DYS464 marker (contained in a section of several million bases)would be called "sporadic" by geneticists. That is, it can occur independently in different individuals from time to time, so a man with the deletion (in the specific sperm that fertilized the egg) could have a brother without the deletion. That section of the Y chromosome is rather prone to deletions because it can loop back on itself and get "pinched off." Check out the Y-chromosome animation on this page, which shows the loop forming in an illustration of recombination:

http://www.hhmi.org/news/page5a.html