Harvard University - Department of Molecular & Cellular Biology


by Cathryn Delude

April 15th, 2012

The annual John M. Prather Lectures in Biology will be presented by Svante Pääbo, an evolutionary geneticist at the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany.

One of the founders of paleogentics, Pääbo developed methods for retrieving and analyzing DNA sequences from archaeological and paleontological remains. He applies these methods to elucidate the history of ancient humans, and Pleistocene mammals, and to compare the genomes of modern humans, our earlier ancestors, and our closest relatives, the apes. He is known for his collaborative effort to reconstruct the Neanderthal genome. In 2010, Pääbo and his colleagues concluded, to widespread surprise, that Neanderthals had interbred with humans in Europe. He also proposes that a new species of hominins (a term that means humans and their ancestors) also contributed to the genomes of humans living outside of Africa, overturning traditional theories of human history.

His public lecture on April 28 lectures will discuss his “leaky replacement” scenario of human origins.

12:00 noon Thursday, April 26: Archaic Genomics

How can we use genomics to fill out the picture of human evolution sketched by the fossil record? Over the past 25 years, Pääbo's laboratory developed techniques for extracting and analyzing DNA from Pleistocene fossil remains. He has used those techniques to reconstruct the genomes of Neanderthals, who lived in western Eurasia until becoming extinct around 30,000 years ago, and to analyze a newly identified human ancestor he calls Denisovans. He has discovered evidence of interbreeding between humans and both Neanderthals and Denisovans, shaking up long-held notions about how our human ancestors interacted with other hominins once they left Africa.

Location: Northwest Lecture Hall B-103.


12:00 noon Friday, April 27: Functional Analyses of a Gene involved in Speech and Language

Why did humans evolve the capacity for language? To investigate the FOXP2 gene that encodes a transcription factor involved in the development of speech and language in humans, Pääbo modified the gene's analog in mice by adding sequences found only in the human version. These "humanized" mice learn more rapidly when required to make transitions from declarative to procedural learning. Pääbo proposes that the ability to rapidly proceduralize motor actions was crucial for the evolution of language and speech.

Location: Northwest Lecture Hall B-103


2:00 PM Saturday, April 28: Human Origins from a DNA Perspective

What can we learn from the DNA of Pleistocene fossil remains? For one thing, about 2.5% of the genomes of people living outside Africa derive from Neandertals, implying that interbreeding occurred between Neandertals and the ancestors of all present-day people living outside Africa. Also, about 4.8% of the genomes of people now living in Papua New Guinea and other parts of Melanesia derive from a hitherto unknown group of hominins called Denisovans, suggesting interbreeding in eastern Eurasia between Denisovans and ancestors of some present-day human groups.

Together, these finding suggest a ‘leaky replacement’ scenario of human origins in which anatomically modern humans emerged out of Africa and received some degree of gene flow from the anatomically archaic human populations in Eurasia that they ultimately replaced. Studying the Neandertal and Denisova genomes allows the identification of novel genomic features that appeared in present-day humans since their divergence from common ancestors with these archaic humans.

Location: Public Lecture, Science Center B

Lectures Schedule Overview:

Thursday, April 26: Archaic Genomics: Departmental Seminar, 12:00 noon, Northwest Lecture Hall B-103. Friday, April 27: Functional Analyses of a Gene involved in Speech and Language: Departmental Seminar, 12:00 noon, Northwest Lecture Hall B-103 Saturday, April 28: Human Origins from a DNA Perspective: Public Lecture, 2:00 pm, Science Center B. Open to the public.

The John M. Prather Lectures in Biology were founded in 1939 by a bequest of $25,000 from John McClellan Prather, A.B. in 1894. The annual income of the fund is to be used to pay for the services of eminent lecturers on botany and zoology alternatively. The Prather Lecture Series on Biology is sponsored by the Department of Molecular and Cellular Biology, the Department of Organismic and Evolutionary Biology, and the Science Center Lecture Series. For more information on the Prather Lecture Series, please call 617.495.5891

[April 15, 2012]