r*s
发帖数: 2555 | 1 Bird eggs are fertilized by more than one sperm, a process called polyspermy
. Penetration by multiple sperm may be unusual in the animal kingdom, but it
is somehow crucial to the development of the bird embryo, a new study finds.
“In humans and mammals, you only need one sperm to penetrate the egg,”
said Nicola Hemmings, an evolutionary biologist at the University of
Sheffield and one of the study’s authors. “If there’s more than one, it
can be lethal and we end up with the embryo dying.”
Dr. Hemmings and her colleagues studied eggs from zebra finches and chickens
. They inseminated the finches with low doses of sperm, from one to 15, and
compared this result with naturally fertilized eggs, which may be fertilized
by 10 to hundreds of sperm.
Dr. Hemmings and her colleagues also inseminated chickens with a low dose of
sperm: approximately 10,000. Other chickens were inseminated with 10
million sperm.
The researchers found that when few sperm penetrated the egg, the bird
embryo was unlikely to survive. They report their findings in the journal
Proceedings of the Royal Society B.
Exactly why the extra sperm are needed is unknown.
“Although the sperm do seem to be required for the embryo to survive, we
don’t know how they contribute to the process of fertilization,” Dr.
Hemmings said. Extra sperm may somehow support cell cycles necessary for
early embryo development.
The research could help scientists develop more successful programs for
endangered species in captive breeding programs, Dr. Hemmings added. | d****o
发帖数: 32610 | 2 是不是得双受精长成胚乳一样的东西
polyspermy
it
finds.
chickens
and
fertilized
【在 r*s 的大作中提到】
: Bird eggs are fertilized by more than one sperm, a process called polyspermy
: . Penetration by multiple sperm may be unusual in the animal kingdom, but it
: is somehow crucial to the development of the bird embryo, a new study finds.
: “In humans and mammals, you only need one sperm to penetrate the egg,”
: said Nicola Hemmings, an evolutionary biologist at the University of
: Sheffield and one of the study’s authors. “If there’s more than one, it
: can be lethal and we end up with the embryo dying.”
: Dr. Hemmings and her colleagues studied eggs from zebra finches and chickens
: . They inseminated the finches with low doses of sperm, from one to 15, and
: compared this result with naturally fertilized eggs, which may be fertilized
| n******7
发帖数: 12463 | 3 看来鸟跟被子植物是近亲
【在 d****o 的大作中提到】
: 是不是得双受精长成胚乳一样的东西
:
: polyspermy
: it
: finds.
: chickens
: and
: fertilized
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