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spermatozoon : ウィキペディア英語版 | spermatozoon
A spermatozoon (pronounced , alternate spelling spermatozoön; plural spermatozoa; from "seed" and "living being") is a motile sperm cell, or moving form of the haploid cell that is the male gamete. A spermatozoon joins an ovum to form a zygote. (A zygote is a single cell, with a complete set of chromosomes, that normally develops into an embryo.) Sperm cells contribute approximately half of the nuclear genetic information to the diploid offspring (excluding, in most cases, mitochondrial DNA). In mammals, the sex of the offspring is determined by the sperm cell: a spermatozoon bearing a Y chromosome will lead to a male (XY) offspring, while one bearing an X chromosome will lead to a female (XX) offspring. Sperm cells were first observed by Anton van Leeuwenhoek in 1677. ==Mammalian spermatozoon structure, function, and size==
抄文引用元・出典: フリー百科事典『 ウィキペディア(Wikipedia)』 ■ウィキペディアで「spermatozoon」の詳細全文を読む
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