[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index][Subject Index][Author Index]
Human male infertility, the Y chromosome, and dinosaur extinction
Sorry, I forgot to change subjects..
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
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.
Sao Paulo, Brazil