#paleogenetics

Svante Pääbo: ‘It’s maybe time to rethink our idea of Neanderthals’

I’d rather not link The Guardian given their terfiness, but I really cant find a better article on this.

Paabo’s winning the Nobel this year for his team’s work extracting DNA from neanderthal remains. Most of the article is biographical, but the Big and Exciting take-away for me here is this quote:

One of the first of many surprises in his research was to find out that the genetic differences between Neanderthals and all modern humans(amounting to about 30,000) are far less than the differences between two random human beings alive today – around 3 million. “Our job is to find out which of those 30,000 are most important, because they tell us what makes us uniquely human,” he says.

At least half of the Neanderthal genome – probably as much as 60 to 70% of it, Pääbo believes – is to be found in living humans. “Which means that in effect Neanderthals are not really extinct at all, they are in us.”

Sometimes, it helps to look at the evolution of science at a sloth’s pace.

In 1990, when Michael Crichton’s newly-released Jurassic Park was kept out of my grip because it was a “grown-up book,” recovering DNA from ancient, extinct organisms seemed like a distant possibility. Scraps of genetic material had been recovered from the quagga – a horse driven to extinction in the 19th century – but finding much older DNA was a scenario better suited to Crichton’s scifi.

Source: https://commons.wikimedia.org/wiki/File:Migraciones_humanas_en_haplogrupos_de_ADN-Y.PNG

The study of genetics of humans, animals, and plants reveals to us the paths of ancient migrations, when domestication took place, and how plants and animals were changed by humanity. The field has about a 110 year history and can unlock genetics as far back as 1.5 million years ago, depending on where the genetic material was deposited.

Source: Wikimedia Commons

The first study of migration through heredity was in 1919 and consisted of the study of ABO blood group distribution between western Europe and India. Ludwik Hirszfeld, a Polish microbiologist, carried out this study, noting that blood type was independent of hair and eye color and that western Europeans were less likely to have blood group A while Indians were less likely to have blood group B. He hypothesized that the difference was the result of was the result of A and B mutating from type O as a result of the environment and through migration or intermingling. His work was continued by Arthur Mourant who expanded the map by investigating blood groups among more populations, leading to the discovery of new blood groups, including the Rhesus system,

Source: https://www.polytechnique-insights.com/en/columns/science/fossil-dna-on-the-trail-of-human-evolution/

The study of DNA within fossils requires that samples be handled very carefully to avoid contamination with modern DNA. Specimens are handled with gloves and stored in a freezer that has a temperature of -20 °C after being removed from the earth. Samples are then prepared and go through a process called polymerase chain reaction, which amplifies how much DNA is in the sample by encouraging replication. Because of this amplification, it is critical to avoid contamination during the process. The change in the environments between the sample being in the ground to it being unearthed can cause rapid degradation and freezing the samples helps prevent that.