Genetic testing has yet to take off in a big way for agriculture, but humans are flocking to the service, geneticist Nicola Dennis writes.

It is 10 years since I hit the streets as a youthful and hopeful science graduate. It was the dawn of the genomics age and it was time to change the entire world with genetic testing.

Well, it is fair to say, genetic testing has yet to take off in a big way for agriculture. However, one industry is going great guns.

Direct-to-consumer genetic testing for humans is a “thing” now. Once, studying the human genome was hard work. It required tedious steps such as applying for funding and proving the study was ethical.

But companies such as “23andMe” have turned that on its head. Why undertake all that legwork when you can simply sell genetic tests directly to people on the internet? The 23andMe database has five million consumers serving as a slightly shady resource for private genetic research and new drug development.

The people of the internet are happy to give up their genome for two main reasons. First, it is a great way to answer some questions about your lineage. If you have someone as distantly related as a fourth cousin already in the database, you will be alerted. Testers can then arrange to put you and your newfound relative in contact with each other. This can be useful for adopted children to track their birth parents (eg: start with a willing distant cousin who is happy to interrogate the rest of their family).

Nothing says “I love you” like dredging up a previously unknown sibling or implicating the giftee in a historic crime. It may be the last present you ever have to buy them.

This method has also been used by the FBI to solve cold-cases. Historic DNA samples from the “Golden State Killer” crimes were matched to 10 or so distance relatives in the “GEDmatch” database and authorities shook the family tree until their suspect fell out.

Not sure what to get that hard-to-buy-for family member this Christmas? How about gifting them a genetic test. Nothing says “I love you” like dredging up a previously unknown sibling or implicating the giftee in a historic crime. It may be the last present you ever have to buy them.

Of course, families with nothing to hide only get a scientifically sketchy, but nevertheless fascinating, report on their ethnic background and how much Neanderthal DNA is in their mix.

The second, much more controversial, reason people buy these tests is to predict their health future. A lot of work is still to be done. For example, it is only possible to explain about 20% of the heritability of human height with genomic testing. That is a little discouraging since height would have to be one of the easiest traits to measure. But it’s a big step from knowing next to nothing 10 years ago.

Observant readers might be a little taken aback to see the terms “heritability” and “human” used in the same sentence. If you are imagining performance recording and breeding values, fear not! Human heritability is usually calculated by recruiting identical twins. If the trait is highly heritable such as height or Alzheimer’s Disease (genetics explains about 70% to 80% of the variation in these traits), then identical twins are likely to have very similar results.

If the trait has a lower heritability and there is more “room” for environmental effects in the trait (dementia, obesity and high blood pressure have a heritability of about 40%) it is more likely that the identical twins have different results (if one twin hits the gym and the other hits the pies, and they end up looking like two sides of a funfair mirror).

Back to predicting health outcomes, 23andMe has FDA approval to report three mutations in the BRCA1 and 2 genes (commonly associated with breast cancer). The company will also report on risk of Alzheimer’s disease, your carrier status for diseases such as sickle cell anaemia, your genetic weight, your ability to match musical pitch and about 90 other things as well.

None of this is available to Kiwi customers because the low accuracy of some of these predictions means the service falls short of NZ consumer laws. However, you may feed the raw results (all 700k DNA markers) into an online service such as Promethease to receive an eyewatering amount of data about health and behavioural traits. It will also make predictions on your hair and eye colour, in case you do not own a mirror.

What an exciting time to be alive, eh? Should consumers be dubious about using these services? Absolutely. But, if anyone wants to get me a genetic test for Christmas, I am happy to out myself and my family as Neanderthals!