w***s
发帖数: 7132 | 1 A new study led by a researcher at the Stanford University School of
Medicine shows that mammalian species can "choose" the sex of their
offspring in order to beat the odds and produce extra grandchildren.
In analyzing 90 years of breeding records from the San Diego Zoo, the
researchers were able to prove for the first time what has been a
fundamental theory of evolutionary biology: that mammals rely on some
unknown physiologic mechanism to manipulate the sex ratios of their
offspring as part of a highly adaptive evolutionary strategy.
"This is one of the holy grails of modern evolutionary biology — finding
the data which definitively show that when females choose the sex of their
offspring, they are doing so strategically to produce more grandchildren,"
said Joseph Garner, PhD, associate professor of comparative medicine and
senior author of the study, published July 10 in PLOS ONE. The results
applied across 198 different species.
The scientists assembled three-generation pedigrees of more than 2,300
animals and found that grandmothers and grandfathers were able to
strategically choose to give birth to sons, if those sons would be high-
quality and in turn reward them with more grandchildren. The process is
believed to be largely controlled by the females, Garner said.
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"You can think of this as being girl power at work in the animal kingdom,"
he said. "We like to think of reproduction as being all about the males
competing for females, with females dutifully picking the winner. But in
reality females have much more invested than males, and they are making
highly strategic decisions about their reproduction based on the environment
, their condition and the quality of their mate. Amazingly, the female is
somehow picking the sperm that will produce the sex that will serve her
interests the most: The sperm are really just pawns in a game that plays out
over generations."
- See more at: http://med.stanford.edu/ism/2013/july/ratios.html#sthash.2upMBdiU.dpuf | M******n
发帖数: 43051 | 2 sex orietation呢？
【在 w***s 的大作中提到】
: A new study led by a researcher at the Stanford University School of
: Medicine shows that mammalian species can "choose" the sex of their
: offspring in order to beat the odds and produce extra grandchildren.
: In analyzing 90 years of breeding records from the San Diego Zoo, the
: researchers were able to prove for the first time what has been a
: fundamental theory of evolutionary biology: that mammals rely on some
: unknown physiologic mechanism to manipulate the sex ratios of their
: offspring as part of a highly adaptive evolutionary strategy.
: "This is one of the holy grails of modern evolutionary biology — finding
: the data which definitively show that when females choose the sex of their
| H********g
发帖数: 43926 | 3 The female monkeys need to get their anthropology degree before they can
agree to this theory. |
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