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Human male infertility, the Y chromosome, and dinosaur extinction



Sorry, I forgot to change subjects..

Hi, folks

Did you notice it?

Sherman J. Silber. 2011. Human male infertility, the Y chromosome, and dinosaur 
extinction. Middle East Fertility Society Journal, In Press, Corrected Proof, 
Available online 17 February 2011 


Study of the molecular genetics of human male infertility and the Y chromosome 
has helped to elucidate the evolution of our X and Y chromosomes. Particularly, 
the study of the Y chromosome in male infertility has also helped to clarify, 
in a surprising and unexpected way, a likely mechanism for dinosaur extinction, 
the biggest question all of us have entertained from our earliest childhood 
days.
There have been many claims in the popular press of “discoveries” on how the 
dinosaurs went extinct. These claims all relate to climate change events that 
occurred 65 million years ago that no one disputes occurred. But none have 
explored the biology of how so many animals escaped extinction while the 
dinosaurs and at least half of all other species did not. For example, why did 
large dinosaurs, as well as small dinosaurs the same size as chickens go 
extinct, but birds survived? Possibly the evolution of sex chromosomes holds 
the answer to this question.
Our studies of the Y chromosome and male infertility suggest that the default 
mechanism for determining the sex of offspring is the temperature of egg 
incubation, and that genetic sex determination (based on sex chromosomes like X 
and Y) has evolved many times over and over again in different ways, in 
different genera, as a more foolproof method than temperature variation of 
assuring a balanced sex ratio in offspring. The absence of such a genetic sex 
determining mechanism in dinosaurs may have led to a skewed sex ratio when 
global temperature dramatically changed 65,000,000 years ago, resulting in a 
preponderance of males, and consequentially a rapid decline in population.


best

Peter Moon
Sao Paulo, Brazil