Human EvolutionGenes and GenomesThe Wandering Gene

Human EvolutionGenes and GenomesThe Wandering Gene

Professor Mark Pallen

Q. How did humans enter Polynesia?

from the West?from the West?from the East?from the East?

A. ...from the West• No convincing human genetic evidence for an

occupation of Polynesia from South America• Native American NRY/mtDNAs very rarely

observed in Polynesians – best explained as the genetic impact of a 19th

century Peruvian slave trade in Polynesia

A. ...from the West• Archaeological evidence– spread of Lapita culture

• Linguistic evidence

A. ...from the West

“Out-of-Taiwan” model of Austronesian expansion‘slow boat (from Asia)’ model of Polynesian origin

• human genetic, linguistic and archaeological evidence converge on Neolithic migrants speaking Austronesian languages expanding from Taiwan about 5.5 kya

• arriving in Melanesia (New Guinea and surrounding islands) about 3.4 kya, where genetic mix with local people while developing the elements of the Lapita cultural complex as well as the Proto-Oceanic language

• Admixture of Asian women and Melanesian men– 96% of Polynesian mtDNA haplotypes are Asian– 2/3 of Y hapotypes are from New Guinea; 1/3 from Asia– Matrilocal residence: daughters stay in the village they were born in and

sons move to their wives' family – Matrilinear in descent: clan affiliation is inherited from the mothers side

• ‘Polynesian motif’ (B4a1a1a) represents the most frequent Asian mtDNA lineage in Polynesia

But it is complicated…

The Arrival of the Maoris in New Zealand, 1898

Oil on canvas, 1380 mm x 2450 mm, Auckland Art Gallery Toi o Tamaki, bequest of Helen Boyd, 1899.

Louis J. Steele and Charles F. Goldie

http://www.cdc.gov/ncidod/eid/vol7no5/cover.htm

Africans with Jewish Origins?

Africans with Jewish Origins?

• Lemba

• Bantu-speaking people of Southern Africa

• Claim Jewish ancestry

• Falasha (Beta Israel)

• Ethiopian Jews

• Claim to be descendants of tribes that came with Menelik I, a son of Solomon and Queen of Sheba

Genome-wide studiesGenome-wide studiesAtzmon et al 2010

• Genome-wide analysis of seven Jewish groups (Iranian, Iraqi, Syrian, Italian, Turkish, Greek, and Ashkenazi) and comparison with non-Jewish groups

• distinctive Jewish population clusters, with shared Middle Eastern ancestry and variable degrees of European and North African admixture.

• Two major groups were identified by principal component, phylogenetic, and identity by descent (IBD) analysis:

- Middle Eastern Jews and European/Syrian Jews.

• refuted large-scale contributions of Central and Eastern European populations to Ashkenazim

• Rapid decay of IBD in Ashkenazi genomes consistent with severe bottleneck followed by large expansion, i.e. “demographic miracle” 50,000 Ashkenazim in 15th century to 5,000,000 in 19th century.

Behar et al 2010

• used high-density bead arrays to genotype

- 14 Jewish Diaspora communities

- 69 Old World non-Jewish populations

• Principal component and structure-like analyses identify previously unrecognized genetic substructure within the Middle East

• Most Jewish samples in tight subcluster that overlies Druze and Cypriot samples but not samples from other Levant populations or paired Diaspora populations

• Ethiopian Jews and Indian Jews (Bene Israel) cluster with neighbouring populations in Ethiopia and western India despite paternal link between Bene Israel and Levant

http://www.ucl.ac.uk/tcga/presentations/ASdemo/AS-26-11-03b.html

Race as a social construction...

• Lewontin (1972) claimed that 85 percent of human variation occurs within populations, and not among populations• argued that neither "race" nor

"subspecies" were appropriate or useful ways to describe populations

• race is ideology, not biology• Is Colin Powell a black man?

Old racist view

View from modern genetics

Genetic Residues of Ancient Migrations: An End to Biological Essentialism and the Reification of Race William M. Richman

University of Toledo

• I am happy to join with you today in what will go down in history as the greatest demonstration for freedom in the history of our nation. Five score years ago, a great American, in whose symbolic shadow we stand today, signed the Emancipation Proclamation. This momentous decree came as a great beacon light of hope to millions of Negro slaves who had been seared in the flames of withering injustice. It came as a joyous daybreak to end the long night of their captivity...

• When the architects of our republic wrote the magnificent words of the Constitution and the Declaration of Independence, they were signing a promissory note to which every American was to fall heir. This note was a promise that all men, yes, black men as well as white men, would be guaranteed the unalienable rights of life, liberty, and the pursuit of happiness...

• I say to you today, my friends, so even though we face the difficulties of today and tomorrow, I still have a dream. It is a dream deeply rooted in the American dream. I have a dream that one day this nation will rise up and live out the true meaning of its creed: "We hold these truths to be self-evident: that all men are created equal."...

• When we allow freedom to ring, when we let it ring from every village and every hamlet, from every state and every city, we will be able to speed up that day when all of God's children, black men and white men, Jews and Gentiles, Protestants and Catholics, will be able to join hands and sing in the words of the old Negro spiritual, "Free at last! free at last! thank God Almighty, we are free at last!"

http://www.usconstitution.net/dream.html

http://en.wikipedia.org/wiki/I_Have_a_Dream

http://www.youtube.com/watch?v=PbUtL_0vAJk

http://www.youtube.com/watch?v=XBa55sDTIiA

Words and ideas are more Words and ideas are more important than genes...important than genes...

First Hawaiian President