Polyspermy in birds: sperm numbers and embryo survival
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چکیده
منابع مشابه
Polyspermy in birds: sperm numbers and embryo survival
Polyspermy is a major puzzle in reproductive biology. In some taxa, multiple sperm enter the ovum as part of the normal fertilization process, whereas in others, penetration of the ovum by more than one sperm is lethal. In birds, several sperm typically enter the germinal disc, yet only one fuses with the female pronucleus. It is unclear whether supernumerary sperm play an essential role in the...
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Ornithologists have known for a long time that males of monogamous bird species sometimes copulate with females from other pairs, but it is only in the last few years that researchers have shown that these extra-pair copulations can result in offspring and increase male reproductive success. Males time their extra-pair copulations to coincide with the period when females are fertilizable, and t...
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Nearly simultaneous fertilization of an egg by two or more sperm (polyspermy) is a lethal condition in most organisms. Sperm competing for an egg face opposing selective pressures. The race to fertilize favours rapid penetration of the egg’s outer protective layer; a close finish between two sperm leads to polyspermy and death. Under most conditions of sperm competition, selection favours maxim...
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Sperm velocity is one of the main determinants of the outcome of sperm competition. Since sperm vary considerably in their morphology between and within species, it seems likely that sperm morphology is associated with sperm velocity. Theory predicts that sperm velocity may be increased by enlarged midpiece (energetic component) or flagellum length (kinetic component), or by particular ratios b...
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ژورنال
عنوان ژورنال: Proceedings of the Royal Society B: Biological Sciences
سال: 2015
ISSN: 0962-8452,1471-2954
DOI: 10.1098/rspb.2015.1682