【正文】 Consists of:,第一百零九頁(yè)，共一百零九頁(yè)。納耶里納表示：“我 們測(cè)試用這種方式(fāngsh236。ir243。,第一百零八頁(yè)，共一百零九頁(yè)。,第一百零六頁(yè)，共一百零九頁(yè)。ng),proportion 比例confidence置信度 fidelity保真度,第一百零四頁(yè)，共一百零九頁(yè)。nx249。,多態(tài)現(xiàn)象,神風(fēng)(sh233。,altruism利他行為,第一百零二頁(yè)，共一百零九頁(yè)。,第一百頁(yè)，共一百零九頁(yè)。,第九十八頁(yè)，共一百零九頁(yè)。,第九十六頁(yè)，共一百零九頁(yè)。,第九十四頁(yè)，共一百零九頁(yè)。,cohort股,一群(yī q,精子發(fā)生,精子形成,第九十一頁(yè)，共一百零九頁(yè)。,第八十九頁(yè)，共一百零九頁(yè)。,第八十七頁(yè)，共一百零九頁(yè)。,第八十五頁(yè)，共一百零九頁(yè)。i)生命周期 Life cycle of humans,第八十三頁(yè)，共一百零九頁(yè)。,人類(r233。nqī) I until sexal maturity, when periodic ovulation（排卵） begins. Groups of oocytes are then stimulated to continue meiosis and mature, and eventually one is ovulated as a secondary oocyte, arrested at prophase II. This block is removed at fertilization . oogenic生卵的 meiosis is asymmetrical, producing only one egg (the other products being discarded as polar bodies). oogenesis in mammals is relatively specialized, and different strategies are used in other species.,第八十一頁(yè)，共一百零九頁(yè)。,Spermatogenesis in mammals Diploid germ cells arriving at the embryonic testis are arrested in the mitotic cell cycle until the animal is born. Now known as spermatogonia(精原細(xì)胞）, the cells proliferate to form a population of stem cells that continuously generate primary spermatocytes（精母細(xì)胞） committed to enter meiosis. Meiosis produces four cells termed spermatocytes committed to enter meiosis. Meiosis produces four cells termed spermatids（精子細(xì)胞）. These undergo extensive differentiation, involving nuclear condensation, ejection of the cytoplasm, and formation of the acrosomal vesicle and flagellum, to form functional sperm. Mammalian specmatogenesis is representative of most of the animal kingdom.,第八十頁(yè)，共一百零九頁(yè)。,3.Germcell migration in vertebrates In Xenopus and mammals, PGCs move from their site of origin to the endodermal cells of the hindgut( 后腸） during gastrulation. They then migrate along the hindgut, across the dorsal mesentery（腸系膜） to the lateral plate mesoderm of the abdominal（腹的） body wall, where they split into two populations and move across to the paired gonadal ridges（生殖(shēngzh237。,2. Germcell migration In Drosophila During gastrulation, the Drosophila pole cells are passively moved from their peripheral 外周的origin to the posterior后面(h242。ngxi224。,2.2 Germcell migration,1.Germ –cell migration 2. germcell migration in Drosophila 3. Germ –cell migration in vetebrates,第七十六頁(yè)，共一百零九頁(yè)。,4.Specification of vetebrate germ line,In xenopus（爪蟾）, the germ line is specified by a vegetal germ plasm comprising distinct yolkfree islands. This migrates to the vegetal pole and is incorporated混合的into cells that’s form the endodermal（內(nèi)胚層(pēic233。,2.Germline specification in Drosophlia（果蠅(ɡuǒ y237。nsh236。n ch243。,1.Overview of germ line specification(特化）,In animals that set aside a germ line in early development ,germcell specification occurs during cleavage or gastrulation. In many cases, this involoves a special area of cytoplasm ,the germ plasm, which is distinguishable in the egg. In such animals ,the formation of germ plasm is dependent on asymmetrically distributed maternal gene products. In birds and mammals, the germ line is not specified by cytoplasmic determinants,but by inductive interactions controlled by zygotic genes.,第七十二頁(yè)，共一百零九頁(yè)。,第七十頁(yè)，共一百零九頁(yè)。,第六十八頁(yè)，共一百零九頁(yè)。,第六十六頁(yè)，共一百零九頁(yè)。,第六十四頁(yè)，共一百零九頁(yè)。,第六十二頁(yè)，共一百零九頁(yè)。,第六十頁(yè)，共一百零九頁(yè)。,第五十八頁(yè)，共一百零九頁(yè)。,第五十六頁(yè)，共一百零九頁(yè)。,第五十四頁(yè)，共一百零九頁(yè)。,第五十二頁(yè)，共一百零九頁(yè)。,第五十頁(yè)，共一百零九頁(yè)。,第四十八頁(yè)，共一百零九頁(yè)。,第四十六頁(yè)，共一百零九頁(yè)。,第四十四頁(yè)，共一百零九頁(yè)。,第四十二頁(yè)，共一百零九頁(yè)。,第四十頁(yè)，共一百零九頁(yè)。,卵子(luǎnzǐ)發(fā)生Oogenesis,Growth,Meiosis I, Cytoplasmic division,Meiosis II, Cytoplasmic division,卵子(luǎnzǐ)(n) ovum (haploid),初級(jí)(chūj237。)精母細(xì)胞,B型精原細(xì)胞,精子細(xì)胞,精子(jīngzǐ),組蛋白,精核蛋白,Ap型精原細(xì)胞,胞質(zhì)橋,第三十七頁(yè)，共一百零九頁(yè)。)精母細(xì)胞,次級(jí)(c236。)：,軸絲,線粒體鞘,第三十六頁(yè)，共一百零九頁(yè)。,(5)精子(jīngzǐ)（spermatozoon）,第三十五頁(yè)，共一百零九頁(yè)。)精母細(xì)胞 (secondary spermatocyte),(4)精子細(xì)胞 ( spermatid ),A型(Ad, Ap ),B型,第三十三頁(yè)，共一百零九頁(yè)。)精母細(xì)胞 (Primary spermatocyte),(3)次級(jí)(c236。)精母細(xì)胞 (secondary spermatocyte),A型(Ad, Ap ),B型,第三十二頁(yè)，共一百零九頁(yè)。)精母細(xì)胞 (Primary spermatocyte),(3)次級(jí)(c236。)(meiosis),第三十一頁(yè)，共一百零九頁(yè)。,精母細(xì) 胞 成 熟 分 裂,減數(shù)分裂(jiǎn sh249。,生 精 細(xì) 胞：,(1)精原細(xì)胞 (spermatogonium),(2)初級(jí)(chūj237。)精母細(xì)胞,(4)精子細(xì)胞,(5)精子(jīngzǐ),第二十八頁(yè)，共一百零九頁(yè)。)精母細(xì)胞,(3)次級(jí)(c236。,生 精 上 皮 ( spermatogenic epithelium ),生 精 細(xì) 胞( Spermatogenic cell ),支 持 細(xì) 胞(sustentacular cell ),第二十七頁(yè)，共一百零九頁(yè)。,（一）生 精 小 管 （ seminiferous tubules ）,生精上皮 基膜 肌樣細(xì)胞(x236。,(一)生精小管（seminiferous tubules）,(二)睪丸(ɡāo w225。n)網(wǎng),直精小管,一、睪丸(ɡāo w225。ng)：,睪丸,生殖管道,附屬腺,外生殖器,產(chǎn)生精子,分泌雄激素,第二十三頁(yè)，共一百零九頁(yè)。ng)生殖系統(tǒng),組成(zǔ ch233。,男性(n225。)尿囊后腸交接處卵黃囊沿背腸系膜左右側(cè)生殖嵴 鳥類和爬行動(dòng)物起源新月區(qū)血液循環(huán)生殖嵴,第二十一頁(yè)，共一百零九頁(yè)。,2.2 原生殖細(xì)胞的遷移 兩棲類通過(guò)卵裂進(jìn)行遷移，植物極分裂溝內(nèi)胚層背腸系膜生殖嵴 哺乳動(dòng)物起源原腸作用胚胎外層原條后部(h242。,2.1生殖細(xì)胞的起源與分化 原始生殖細(xì)胞（primordial germ cell,PGC）遷移(qiāny237。,第十八頁(yè)，共一百零九頁(yè)。 研究小組對(duì)雌性鳉魚進(jìn)行基因操作，使其卵巢內(nèi)的卵發(fā)出紅光，結(jié)果發(fā)現(xiàn)了很多即將發(fā)育為卵的細(xì)胞。)發(fā)現(xiàn)可發(fā)育成卵的干細(xì)胞,日本一個(gè)研究小組日前發(fā)現(xiàn)，在雌鳉魚的卵巢內(nèi)存在可發(fā)育成鳉魚卵的干細(xì)胞。該研究發(fā)表在《生物學(xué)評(píng)論》雜志上,第十七頁(yè)，共一百零九頁(yè)。哈森相信，這些超級(jí)精子會(huì)有效越過(guò)女性身體的防衛(wèi)，以致于不只一個(gè)精子刺破同一個(gè)卵子(luǎnzǐ)。nɡ)過(guò)快可能導(dǎo)致不孕,一項(xiàng)最新的研究顯示，有些人當(dāng)不上父親可能是因?yàn)樗麄儺a(chǎn)生的是超級(jí)精子，它們游動(dòng)得太快太有力。,2009915 11:00:47 Biological Reviews：男性超級(jí)精子游動(dòng)(y243。,Competition drives cooperation among closely related sperm of deer mice Heidi S. Fisher1,2 amp。 xiāng)連接起來(lái)，協(xié)力向前游動(dòng)，這樣一列“精子火車”的速度比單個(gè)精子要快約50％，四分之三相同來(lái)源的精子都會(huì)加入這樣的隊(duì)列中。,第十四頁(yè)，共一百零九頁(yè)。一旦改變培養(yǎng)條件，就會(huì)分