The Development and Evolution of the Human Brain
Pollard KS, Salama SR, Lambert N, Lambot M-A, Coppens S, Pedersen JS, Katzman S, King B, Onodera C, Siepel A, Kern AD, Dehay C, Igel H, Ares M Jr, Vanderhaeghen P, Haussler D. 2006. A rapidly evolving region in the human genome is an RNA gene expressed during early neocortical development. Nature 443(7108):167-72.
Briefly tell us a bit about yourself, your career path over the years, and specifically what led you to begin working on human evolution.
You talk about recombination hotspots in the human versus chimpanzee. Could you please explain more about what they are, why they are important, and how you think they came to evolve differently in human and chimpanzees?
The researchers discovered that Shh-mediated chemoattraction appears to require Smo function. This result was not anticipated however because there is no clear pathway from activated Smoothened to the cytoskeleton rearrangements required for growth cone turning. Is a pathway from activated Smoothened to the cytoskeleton being further investigated? Specifically, how does the intracellular machinery differ in commissural neurons to cause outgrowth in response to Netrin-1 and turning rather than outgrowth in response to Shh?
You explained that HAR1R may be expressed later in development to downregulate HARIF by antisense inhibition. If HAR1R is antagonizing HAR1F expression, what can we conclude about their role in mice where they are expressed at similar levels?
Concerning the role of HAR1F and HAR1R in cortical development, are you doing any further research to determine whether HAR1F influences the expression of reelin or its receptors or acts through a different pathway all together? If so, what have you found? Do you have any functional evidence to suggest that Har1 genes are actually necessary for cortical development?
The results of RNA in situ hybridzation of adult human tissues found both the HAR1F and the HAR1R transcripts in the ovaries and testes. What do you propose might be the reason that they would be expressed there? Is expression in the ovaries and testes conserved in other species?
Currently in your opinion what are the most pressing questions in the field of human evolution, and what steps are you taking to address those questions?