Category: Genetics
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The “X” in the sex chromosome
There are ~3 billion base pairs in the human genome. Of that ~5% are in the X chromosome. The X is fully functional, unlike the famously hamstrung Y. It harbors one of the longest genes in the human genome, DMD, at 2,300,000 base pairs. In contrast, th…
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The genetics of forensic identification
The arrest of a suspect in the infamous “Golden State Killer” DNA evidence was notable for how he was identified. The media attention the case has garnered means that forensics genetics have come to public attention again in 2018. Not that the public h…
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Closing the genetic chapter
Indus Valley People Did Not Have Genetic Contribution From The Steppes: Head Of Ancient DNA Lab Testing Rakhigarhi Samples: In other words, the preprint observes that the migration from the steppes to South Asia was the source of the Indo-European languages in the subcontinent. Commenting on this, Rai said, “any model of migration of Indo-Europeans…
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DNA, from genetics to genomics
In the early 1950s scientists established that the molecular structure of DNA was a double helix. The had discovered the physical substrate of heredity. With this discovery the field of molecular genetics was born (and eventually a Nobel Prize given!)….
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The water rises and Canute drowns
The Genetic History of Indians: Are We What We Think We Are?. The answer is that people of all races have always been what they always were. What we think about what we were…well, that changes. “I KNOW PEOPLE won’t be happy to hear this,” geneticist Niraj Rai says over the phone from Lucknow. “But…
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The braided estuary of human evolution
Metaphors matter because they evoke images, and images are often one of the best ways to understand something in a deep fashion. Consider Charles Darwin’s musing:“It is interesting to contemplate a tangled bank…”He brought something memorable and famil…
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The “g” in genes
What’s next?Intelligence, or smarts, is once of those words which has many meanings. That’s why we say “street smart” or “book smart.” When psychologists speak of intelligence, however, they are usually referring to something more precise and specific….
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The Jewish people: genetic unity in diversity
The Western WallThe religion of the Jews has had a great influence on the history of the world. Both Christianity and and Islam look to the Jewish tradition. Figures such as Moses are iconic in the Abrahamic context as lawgivers, setting a precedent fo…
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South Asian genetics, the penultimate chapter
A long post at my other blog, The Maturation Of The South Asian Genetic Landscape, a reflection on the important preprint The Genomic Formation of South and Central Asia. Shorter: The original inhabitants of the Indian subcontinent who descent from the “out of Africa” migration separated very quickly, ~50,000 years ago, from other eastern populations…
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The Indian chapter of Who We Are and How We Got Here
Since Who We Are and How We Got Here is out I thought I would spoil the “India chapter” (though you should buy the book!). – The “Ancestral North Indians” are best modeled as a 50/50 ratio of Yamna-type people from the steppes & “Iranian farmers.” The implication is that the Indo-Aryans mixed with agriculturalists…
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Complex traits to individual predictions
The classical model of genetic inheritance, which dates back to the 19th century, involves discrete traits that are transmitted across generations in easily detectable patterns. These patterns follow what is known as a “Mendelian” model of inheritance: first adopted by the Austrian monk Gregor Mendel, based on his work with pea breeding in the mid-19th…
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“Because we could”
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The Others were people too
Neanderthals, cousins we knew.In 2010, our understanding of Neanderthals, our human cousins, changed forever. Before this year, there was a live debate about whether they were human at all, whether they had fully elaborated language, or even culture.Wh…
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Caste in Punjab
Punjabi Genetic Variation In 1000 Genomes: Hindu Caste In The Land Of The Pure?. I don’t know much about caste in Punjab (Pakistan) at all. But there’s a lot of genetic structure in this Lahore sample (these are people who claim their paren…
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Punjabi genetic variation in 1000 Genomes: Hindu caste in the Land of the Pure?
In the 1000 Genomes, there is a Punjabi dataset. Here is the description: These cell lines and DNA samples were prepared from blood samples collected in Lahore, Pakistan. The samples are from a mix of parent- adult child trios and unrelated individuals who identified themselves and their parents as Punjabi. A few years ago I…
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South Asian genetic relationships
At my other blog. Some charts.
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Notes on South Asian genetics, 2018
In the post below Zach observes that the progressive author of a piece criticizing Ajit Pai has to note she too is a Gaud Saraswat Brahmin. Of course, she is progressive and opposes casteism no doubt. But to me “caste-dropping” that you are a Brahmin is like criticizing standardized testing, while observing that you also aced…
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Continuous gene flow vs. pulse admixture
In the new preprint Ancient genomics: a new view into human prehistory and evolution the authors write: The geographic structure of these population transformations gave rise to population structure of present-day Europe. For example Anatolian Neolithic ancestry is highest in southern European populations like Sardinians, and lowest in northern European populations (38). Steppe ancestry is…
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Continuous gene flow vs. pulse admixture
In the new preprint Ancient genomics: a new view into human prehistory and evolution the authors write: The geographic structure of these population transformations gave rise to population structure of present-day Europe. For example Anatolian Neolithic ancestry is highest in southern European populations like Sardinians, and lowest in northern European populations (38). Steppe ancestry is…
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Recollections of Mel Green
Terrible news: I just heard that Mel Green passed away. — Andrew Kern (@pastramimachine) October 24, 2017 Mel Green co-taught a “history of genetics” course that I took as a first-year grad student at UC Davis. It was fitting because Mel Green was a living embodiment of the history of genetics. Mine was one of…