D睾丸酮 (testosterone):由睾丸间质细胞合成,其作用是 诱导中肾管分化为输精管、精囊、附睾。 Figure 20.9 An XY individual with androgen insen sitivity syndrome. Despite the XY kary otype and the presence of testes, the individual develops female secondary sex characteristics. Internally, however the woman lacks the Mullerian duct derivatives and has undescended testes Courtesy of C B. Hammond. 该患者携带SRY基因 testes AMH-+Mullerian duct degeneration uterus、 oviduct testosterone No androgen receptor 输精管、精囊、附睾
Developmental Biology 睾丸酮(testosterone) ：由睾丸间质细胞合成，其作用是 诱导中肾管分化为输精管、精囊、附睾。 该患者携带SRY基因 testes AMH Mullerian duct degeneration uterus、oviduct testosterone No androgen receptor 输精管、精囊、附睾
D 二氢睾丸酮 testosterone):由睾丸酮转变而成,其作用 是控制外生殖器官的形成。缺少5a- ketosteroid reductase2的XY个 体的外形像 female Urinary bladder Rectum Pubis Seminal sicle Prostate Penis Urethra Vas deferens Epididymis Testis Dihydrotestosterone-dependent Testosterone-dependent Figure 20.10 Testosterone- and dihydrotestosterone-dependent regions of the fetal human male genital system.(After Imperato-McGinley et al., 1974)
Developmental Biology 二氢睾丸酮(testosterone) ：由睾丸酮转变而成，其作用 是控制外生殖器官的形成。缺少5a-ketosteroid reductase 2的XY个 体的外形像female
Developmental Biology 雌激素( estrogen) 在 female胚胎中,雌激素由卵巢合成,它诱导 Mullerian duct分化为雌性器官。 在male胚胎中,雌激素由肾上腺合成,它使中肾 旁管细胞吸收睾丸中的水分,有助于增加精子的寿命 和数量
Developmental Biology 雌激素(estrogen) ： 在female胚胎中，雌激素由卵巢合成，它诱导 Mullerian duct分化为雌性器官。 在male胚胎中，雌激素由肾上腺合成，它使中肾 旁管细胞吸收睾丸中的水分，有助于增加精子的寿命 和数量
Developmental Biology (二)、果蝇的性别决定 1.果蝇的性别决定于X染色体的数量: X染色体上的性别决定基因叫分子基因( numerator),而 常染色体上的性别决定基因叫分母基因( denominator)。二者 之比≤0.5时,个体将发育为雄性。 Table 20.1 Ratios of X chromosomes to autosomes in different sexual phenotypes in Drosophila melanogaster X chromosomes Autosome sets (a) X: A ratio Sex 150 Metafemale 34432211 23432323 1.33 Metafemale 1.00 Normal female 1C0 Normal female 1.00 Normal female 0.66 Intersex 0.50 Normal mal 0.33 Mctamale
Developmental Biology (二)、果蝇的性别决定 1. 果蝇的性别决定于X染色体的数量: X染色体上的性别决定基因叫分子基因(numerator)，而 常染色体上的性别决定基因叫分母基因(denominator)。二者 之比 0.5时，个体将发育为雄性
Developmental Biology 果蝇的雌雄嵌合体 Figure 17.15 Gynandromorphs. ( A) Gynandromorph of D, melanogaster in which the left side is female (XX)and the right side is male(XO). The male side has lost an X chromosome bearing the Gynandromorph happens wild-type alleles of eye color and wing shape, thereby allowing the expression of the recessive when an x chromosome is Ing gynandromorphic lo moth, divided bilaterally into a rose- brown female half and a smaller, lost from one embryonic yellow male half.(A from Morgan and Bridges 1919, drawn by Edith Wallace. B: photograph nucleus by T. R. Manley, courtesy of The Journal of Heredity.) (B) Wild eosin eye cosIn eye type nmintantrc wing )MINiature wIng XO
Developmental Biology 果蝇的雌雄嵌合体 Gynandromorph happens when an X chromosome is lost from one embryonic nucleus