Chapter 5 Linkage and gene mapping 第五章连锁遗传与遗传作图 Linkage, recombination and crossing over连锁现象、重组和交换 Genetic mapping(色体作图 Sex-linked inheritance and sex determination伴性遗传和性别决定
Chapter 5 Linkage and gene mapping 第五章 连锁遗传与遗传作图 ◼ Linkage, recombination and crossing over 连锁现象、重组和交换 ◼ Genetic mapping染色体作图 ◼ Sex-linked inheritance and sex determination伴性遗传和性别决定
Sweet pea flo Strains differing in X two traits, flower and poll Pollen grains grain length, are Long pollen grains White flowers Red flowers crossed short pollen gra Linkage F 2 The hybrids are one of the 连锁现象 parental strains, Red flowers indicating that red Long pollen grains flower is dominant over white and that long pollen grains is dominant over short Red flowers Red flowers White flowers White flowers Long pollen Short pollen Long pollen Short pollen grains grains grains grains 24 170 (Parental (Recombinant) (Recombinant) (Parental The frequencies of the four classes of F2 progeny deviate signifi- cantly from the Mendelian expectation of 9/16, 3/16, 3/16, and 1716, indicating that the genes controlling the trait are linked
Linkage 连锁现象
Bateson and pune什的试验(一) P 紫花、长花粉粒ⅹ红花、圆花粉粒 PPLL ppll F 紫花、长花粉粒 PpLI F 紫长紫圆红长红圆总数 P-L- P- ppL- ppll 实际观察数 483139039313386952 按9:3:3:13910.51303.51303.5434.56952 推算的理论数
P 紫花、长花粉粒 × 红花、圆花粉粒 PPLL ppll F1 紫花、长花粉粒 PpLl F2 紫长 紫圆 红长 红圆 总数 P-L- P-ll ppL- ppll 实际观察数 4831 390 393 1338 6952 按9:3:3:1 3910.5 1303.5 1303.5 434.5 6952 推算的理论数 Bateson and Punnett的试验(一)
Bateson and pune的试验(二) 紫圆PP×红长ppLL 紫长PpL F 紫长紫圆红长红圆总数 P-L- P-l ppL- ppll 实际观察数2695951 417 按9:3:3:1235.878578526,2417 推算的理论数
P 紫圆PPll × 红长ppLL F1 紫长PpLl F2 紫长 紫圆 红长 红圆 总数 P-L- P-ll ppL- ppll 实际观察数 226 95 95 1 417 按9:3:3:1 235.8 78.5 78.5 26.2 417 推算的理论数 Bateson and Punnett的试验(二)
摩 亲本杂交bpr×++ 尔 b pr 根 测交bpr 的 b pr b pr 果 表型观察值独立分配的预期值 嘱子代bPr黑体 374 193 杂 亲本型bpr紫眼 ++野生型398 193 交 pr 试 重组型b 黑体 193 b pr t pr 紫眼 193 b pr 总和 772 772
摩 尔 根 的 果 蝇 杂 交 试 验 1 亲本杂交 b pr + + b pr + + 测 交 b pr + + b pr b pr 表 型 观察值 独立分配的预期值 子 代 b pr 黑体 374 193 亲本型 b pr 紫眼 + + 野生型 398 193 b pr 重组型 b + 黑体 0 193 b pr + pr 紫眼 0 193 b pr 总和 772 772
亲本杂交bprX+ b pr 摩尔根的果蝇杂交试验 测交bpr b pr b pr 表型观察值独立分配的预期值 子代bpr黑体210 120 亲本型bpr紫眼 野生型240 120 pr 重组型b+ 黑体 14 120 b pr t pr 紫眼 16 120 b pr 总和 480 80
摩 尔 根 的 果 蝇 杂 交 试 验 2 亲本杂交 b pr + + b pr + + 测 交 b pr + + b pr b pr 表 型 观察值 独立分配的预期值 子 代 b pr 黑体 210 120 亲本型 b pr 紫眼 + + 野生型 240 120 b pr 重组型 b + 黑体 14 120 b pr + pr 紫眼 16 120 b pr 总和 480 480
Linkage连锁遗传现象 Linkage: the genes should travel as a unit through meiosis because they are physically attached to the same strucfure 连锁遗传现象:亲本所具有的两个性状 在F2中常常联系在一起而遗传的现象
Linkage: the genes should travel as a unit through meiosis because they are physically attached to the same structure. 连锁遗传现象:亲本所具有的两个性状 在F2中常常联系在一起而遗传的现象。 Linkage连锁遗传现象
Explanation for linkage 连锁遗传现象的解释 Red. lon Red. lon ■ The gene for (Self-fertilized) R different characters Parental Recombinant Recombinant Parental are located on the same chromosome Parenta 两个非等位基因处 在一对同源染色体 R 上 Recombinant G White, long Rt R Parental Red short white, lng vArre short
◼ The gene for different characters are located on the same chromosome. 两个非等位基因处 在一对同源染色体 上 Explanation for linkage 连锁遗传现象的解释
Frequency of recombination as a measure of linkage intensity Calculation of frequency of recombination The most direct way of estimating the frequency of recombination is to use a testcross Linkage phase连锁相 Coupling相引 Repulsion相斥
Frequency of recombination as a measure of linkage intensity ➢ Calculation of frequency of recombination ✓ The most direct way of estimating the frequency of recombination is to use a testcross ➢ Linkage phase 连锁相 ✓ Coupling 相引 ✓ Repulsion 相斥
A test cross for linkage O A heterozygote for two linked genes is testcrossed to a recessive homozygote. R L Coupling and repulsion 包國 Red, long White, short linkage phases in double heterozygotes hEgm在双杂合子中的相引相和 回励 相斥相 Red, long Red, short White, long White, snort 450 42 38 470 Coupling Repulsion heterozygote heterozygote 80 recombinant R L 920 parental Frequency of recombinants 8008 80+920 O The low frequency of recombination indicates that the genes are rather tightly linked
A test cross for linkage Coupling and repulsion linkage phases in double heterozygotes 在双杂合子中的相引相和 相斥相