Gene from extinct species allows Tibetans to live at high altitude

The roof of the world, north of the Himalayas, stretches over two and a half million square kilometres. It is inhospitable, arid and permafrosted. When it rains, it mainly hails. It’s the highest place on the planet where you can stand on flat ground and be near the heavens, and standing there will thicken your blood. Unless you carry the EPAS1 gene.

This gene stops you over-producing haemoglobin – the oxygen-carrier in red blood cells. Too much haemoglobin raises blood pressure and, with it, the risk of stroke, among other bloody things.

This gene came from an ancient, extinct subspecies of human called the Denisovans. We know this because scientists sequenced Denisovan DNA four years ago. This DNA came from a fragment of a pinky and two teeth found in a cave.

The ancestors of today’s Tibetans had sex with Denisovans. Genes were passed around. The useful ones remained. This allows Tibetan people to survive on the roof of the world.

I wrote about the science for this week’s BioNews. Have a read.

Replica of Denisovan pinky bone (Source: National Geographic)

Review of PET’s ‘Breast Cancer, Business and Patents’: Ensuring your genes don’t affect your insurance

I tried to make insurance interesting on behalf of the Progress Educational Trust (PET) and the Wellcome Trust. Have a read.

The piece comes from PET’s recent event ‘Risk Management: Breast Cancer, Business and Patents’ — the third of their four-part project ‘Breast Cancer: Chances, Choices and Genetics’.

Simon Hazelwood-Smith reviewed the night for BioNews.

James Heather covered the second event — Risk Assessment: Breast Cancer, Prediction and Screening.

I covered the first one for BioNews and James wrote it up for the Wellcome Trust blog.

The final event — Breast Cancer Risk: Facts, Fictions and the Future — is taking place on Thursday 3rd July. See PET’s website for more details.

Genetic ancestry test claims to find ‘village where your DNA was formed’

This week for BioNews, I report on a genetic astrology ancestry test that claims to “tell you where your DNA was forged, and is accurate to home village with a time resolution of the past 1,000 years.” Researchers named the test Geographic Population Structure, or GPS, presumably to convey a sense of satnav-esque accuracy.

The method was published to a fanfare of overblown press releases and uncritical media coverage.

“What we have discovered,” spun one of the press releases, “is a way to find not where you were born – as you have that information on your passport – but where your DNA was formed up to 1,000 years ago by modeling these admixture processes.”

At the same time, the researchers founded a company called Prosapia Genetics which tells you your supposed ancestral homes in exchange for money.

But it doesn’t work so well. Some customers found their ancestral genomes stuck slap-bang in an ocean:

A GPS test dropped in the ocean (source: Prosapia Genetics)
A GPS test dropped in the ocean (source: Prosapia Genetics)

This is because the tool averages between the locations of genomes for which it has geographical data. Apparently it’s meant to work this way. Dr Eran Elhaik – one of the study’s co-authors – wrote on Prosapia’s forum: “when you have British and Chinese parents you will be predicted to Iraq, as it is in the middle of the two gene pools.”

Many in the know have dismantled the science far better than I ever could. Debbie Kennett writes a wonderfully comprehensive account. Pseudonymous blogger Dienekes Pontikos explains some of the wrongness in the tool amid hints of plagiarism. And Joe Pickrell – who peer-reviewed the study – posted a summary of his problems with the paper.

According to the Prosapia website, the scientists are developing an extended tool – GPS2 – that will apparently show two parent groups that formed your DNA, rather than just one. (If you trace back 10 generations – around 300 years, for sake of argument – you have up to 1,024 genealogical ancestors but you contain DNA from only maybe 120 of them. See Luke Jostins’ blog for an explanation.)

Anyhow, I’m writing a longer comment piece for BioNews that will be out next Monday and will go into more detail there.

In the meantime, have a read:

Relative Risk: Breast Cancer and Genetics — Review for the Progress Educational Trust

Last week, the Progress Education Trust launched a new project called ‘Breast Cancer: Chances, Choices and Genetics’, inspired by Angelina Jolie’s risk-reducing mastectomy surgery. It’s a topic I was previously keen on avoiding. I hoped to get through an entire science-writing career without using the ‘C’ word, but alas. I’ve reviewed the first of the four events for BioNews (have a read then come back here).

By dint of deadlines and word counts, I had to leave out so much I wanted to say about the evening. The rest of this post contains a hodgepodge of offcuts from my review.
Continue reading “Relative Risk: Breast Cancer and Genetics — Review for the Progress Educational Trust”

Y: The (not quite) Last Man

Human males will not exist in five million years’ time. So goes a popular line of thinking. But maybe it’s not quite right.

This week for BioNews, I report on a study that draws on 16 complete, high-coverage genomes and a bunch of mathematical models to show that the ‘male’ Y chromosome will be sticking around for a while. The little bastard may contain only 27 genes but they seem to be 27 genes that natural selection is holding onto.

Have a read.

Reference: Wilson Sayres, Lohmueller & Nielsen (2013). Natural selection reduced diversity on human Y chromosomes PLOS Genetics DOI: 10.1371/journal.pgen.1004064