遗传学 第7章 温度性别决定

Chelydra serpentina
Bowden et al., 2000
Elf, 2003
“温度-性激素”性别决定模型示意图 Sketch map of “Temperature-Hormone” Sex Determination Model.
环境性别决定
Environmental sex determination（ESD） light, temperature ……
环境性别决定
Environmental sex determination（ESD）
温度依赖型性别决定
Temperature-dependent sex determination
Alligator mississippiensis
Temperature
TSP 大约处于胚胎发 育整个过程的中间 1/3 时期
5.9day
100
Initial at 32 C
hatch
o
6 5
D
Sex ratio (%Female)
Leabharlann Baidu
80
y = 26.88 + 67.75e
-e-(
x - 5.88 4.42
10 3
4 1 10 3 9
7 9 3
G= 3.35, df = 4, P = 0.501
海南睑虎6 24 °C
Hemidactylus frenatus GSD Wuzhishan (Hainan)
G= 0.13, df = 2, P = 0.937
温度性别决定的爬行类的性腺分化
皮质 temperature-sensitive period (TSP) 髓质
)
, r = 0.98
2
4
Tangent slope
3 60
y' = 15.33e
-[(x-5.88) + e-(
4.42
x-5.88 4.42 )]
2 1
40
TSP
7-44%
20 0 6 12 18 24 30 36 42
0 -1
Days before change temperature
类固醇激素 (steroid hormone )
Female-Male
Female-Male-Female
Male-Female
非洲红头岩蜥（Agama agama）
Charnier, 1966
Eulamprus tympanum
Robert & Thompson, 2001
Fish Amphibia Mammalia
SDMs
More diversity !
TSD
Shouguang (Shandong)
G= 13.50, df = 2, P < 0.002
原尾蜥虎
22 °C 24 °C 27 °C 28 °C 32 °C
28 °C 32 °C
截趾虎
Hemidactylus bowringii
GSD
Zhaoqing (Guangdong)
7 1 9 2 7
疣尾蜥虎
G= 8.22, df = 2, P < 0.02
Gekko japonicus
TSD
Longnan (Jiangxi), Chuzhou (Anhui) & Nanjing (Jiangsu)
G= 44.70, df = 4, P < 0.0001
Gekko swinhonis Hemidactylus
关键作用
TSD爬行类性腺发育
改变睾酮（T），二氢睾酮（DHT）及雌二醇（E2）的含量 都会改变后代性别
早期研究方法：卵表面滴加，母体体内包埋等方式
29.4 oC
芳香化酶抑制剂的作用
Experimental manipulations
E2
More females in male-prouducing temperature
Temperature-dependent sex determination in reptiles
Guo-Hua Ding Ph.D. guohua_ding@hotmail.com
XY / XX
ZW / ZZ
基因性别决定
性别决定
Sex determination
Genotypic sex determination（GSD）
无蹼壁虎
多疣壁虎 2
2 1 G= 0.68, df = 2, P = 0.712
Gekko
Gekko hokouensis TSD Shaoxing (Zhejiang)
铅山壁虎
24 °C 28 °C 32 °C 22 °C 24 °C 27 °C 28 °C 32 °C 24 °C 28 °C 32 °C 15 21 4 2 7 14 32 9 1 5 2 32 19 18 22 42 6 33 51 5 0 10
Reptilia
Janzen & Phillps, 2006
无蹼壁虎
多疣壁虎 铅山壁虎
卵孵化： 22-32C范围内恒温孵化 性别鉴定： 120天个体：雄性第二性征 （尾基部隆起） 45-120天个体：解剖观察性腺
疣尾蜥虎
截趾虎
原尾蜥虎
Ovary
Testis
海南睑虎
Gekkota Genus Species Goniurosaurus Goniurosaurus lichtenfelderi Gehyra Gehyra mutilata GSD Wuzhishan (Hainan) 24 °C 28 °C 32 °C 2 1 2 TSD Wuzhishan (Hainan) 22 °C 24 °C 26 °C 14 23 45 28 25 22 G= 12.59, df = 2, P < 0.002 Sex-determining mechanism Natural geographic origin Incubation temperature Males Females Log-likelihood ratio test (G-test)
5ug/ul
Amphibolurus muricatus
Bassiana duperreyi
Naturally
Chelydra serpentina
Alligator mississippiensis
Eublepharis macularius
In several TSD species, there has been evidence that maternally derived yolk steroid hormones can influence offspring sex.
T
More males in female-prouducing temperature
More males in the 1:1 ratio temperature More males in female-prouducing temperature
DHT
Aromatase inhibitor
皮质酮（Corticosterone）