Nicholas Wade's "Before the Dawn"

Before the Dawn by Nicholas Wade is a delightful romp through the application of current research in genetics to the last 50,000 years of human evolution.


Some of the delightful insights of the book:

• The genetics of body lice help to date the first human clothing to 72,000 years ago.
• Human body hair as decoration dates back 200,000 years ago with inactivation of genes that control the growth & quiescence cycle of normal fur.
• Truly modern human behaviour (culture) dates back only 50,000 years ago and is coincident with the achievement of fully modern speech.
• The discovery of that a defective FOXP2 gene inhibits normal speech and that this gene is highly conserved over 70 million years, but over the last 5 million years as the human line diverged from the ape line it has undergone two changes indicating that it is under strong evolutionary pressure.
• The roots of modern humans are in the sub-Saharan as small tribes of hunter gatherers who probably spoke a click language related to Khoisan.
• The earliest exodus of modern humans was via the sea's edge and followed the cost of south Asia all the way to Australia (the continent of Sahul). It requires rafting/boating to pass from the horn of Africa via the 12 mile sea at the Gates of Grief to southern Yemen and it required more substantial boats to cover the 60 miles of open water between the lost continents of Sunda and Sahul.
• The relict Homo Erectus hindered penetration of east Asia and the relict Neanderthal hindered penetration of western Asia/Europe.
• The Upper Paleolithic saw a number of modern human cultures flourish as climate change brought bouts of Ice Age extension that pushed survivors into southern redoubts: Aurignacian, Gravettian, Solutrean, and Magdalenian. Each cycle of isolation and then expansion allowed population bottlenecks to drive genetic differentiation.
• The dog was domesticated 15,000 years ago.
• Humans drove the Neanderthals to extinction around 30,000 years ago, entered the Americas 14,000 years ago and the last expansion in the Pacific was to New Zealand in 1200 AD.
• It was evolution of our mitochondrial DNA that fitted us to penetrate the cold Eurasian landmass.
• Settlement preceded agriculture in the earliest switch from hunter gatherer to agricultural lifestyle. There was a genetic accomodation required to reduce the level of hostility to allow larger groups to live a settled life.
• Cattle herding dates back to 6,000 years ago with the Funnel Beak culture and required a genetic accommodation via lactose tolerance to take advantage of the new food source. Genetics puts the centre of cattle domestication in north-central Europe. The highest lactose tolerance is among human populations centred in north-central Europe reaching 100%.
• The Romantic picture of peaceful, in-tune-with-nature primitives is a myth. Primitive humans suffered higher violent deaths than civilized people despite the carnage of modern wars. Primitive battles typically resulted in 30% casualties, more than what were experienced at Gettysberg. Typically 65% of all primitive societies are at war at any given time and primitives suffer an annual 0.5% death rate from violence.
  
• Kinship ties spell life over death. In the Mayflower 51% of the colonists died in the first year. Those who had no kin were more likely to die than those who had kin. In the Donner party stranded in the Sierra Nevada, only 3 of 15 single men survived while the typical survivor had 8.4 family members with him.
• Human evolved the levels of oxytocin and vasopressin to allow living in larger units. Our behaviour evolution included the development of a trust to act as social glue. In order to minimize "freeloaders" we developed religion as a belief system requiring commitment and those who broke the trust were shunned or exiled.
• Humans are "domesticated". Our skeletons are gracilized as we have lowered the level of violence and come to live in larger societies.
• Settled societies depend on the strengthening of two traits in hunter gatherer societies: reciprocity and leadership.
• Race is a natural result of differentiation based on genetic isolation. It has a genetic basis. There is a clustering of human DNA into 5 groups: Africans, Caucasians, Asians, Pacific Islanders, and Native Americans. (Modern medicine is starting to take note of racial differences because drug responses can vary by racial group.)
  
• Language correlates with modern human dispersion patterns. The linguist Joseph Greenberg has developed a universal classification of linguistic evolution. Using statistical techniques similar to genetic studies, historical dating of the evolution of languages is becoming possible. Indo-European languages date back to 8,700 years ago and correlate with the spread of agriculture out of the Middle East. (The alternative hypothesis was that Indo-European dates from the Kurgan warrior expansion of 6,000 years ago from the steppe area north of the Black Sea.)
• Men seek power to get reproductive access, and it works: (a) 8% of all Asian men in the lands rules by the Mongols carry Genghis Khan's Y chromosome that dates back to 1200. (b) 1.6 million Asian have the Y chromosome of Giocangga, the patriarch of the Manchu dynasty, dating back to 1644.
• Genetics can solve some mysteries. Thomas Jefferson sired a family with the slave mistress Sally Hemmings. His affair started when he brought the 13 year old Sally to France while he was posted as American ambassador there. She was free in France, but he persuaded her to return as his slave by promising to free his children by her, and he did. But he never spent any time with his black offspring (i.e. showed no "fatherly affection"). They would not have learned to read except some of the white children in the Jefferson household taught them. The reason why Jefferson took Sally Hemmings as his mistress was that she was his wife Martha's half sister since she was the offspring of the slaveholder John Wayles. Apparantly Sally Hemmings had a strong resemblance to her half-sister Martha Wayles who became Jefferson's wife. It is odd that the author of the Declaration of Independence who wrote the ringing words "we hold these truths to be self-evident that all men are created equal" would be a slaveholder who used his position to have sex with his slaves.
• There is strong evidence of on-going human genetic evolution, especially in our response to deadly diseases: malaria, black plague, small pox, etc. Apparantly the Caucassian response on the CCR5 receptor, in response to small pox, has made this population resistent to AIDS.
• Wade speculates that the European environment put selective pressure on the European population to accommodate ideas of individualism, freedom, consensual government, and an open economy. He sees the Chinese civilization with its organization favoured conformism. (These are speculations for which he offers no real scientific evidence, but are meant to encourage thinking about how evolution is on-going and how our environment is shaping human populations.)