在Arabidopsis的内生繁殖的成本
Carlos D Bustamante1, Rasmus Nielsen, Stanley A Sawyer
1Department of Organismic and Evolutionary Biology, Harvard University, 16 Divinity Avenue, Cambridge, Massachusetts 02138, USA.
Nature
|April 5, 2002
概括
果主要表现出有益的基因变化,而阿拉比多普西斯植物表现出有害的变化. 这种差异与Arabidopsis有关.
科学领域:
- 人口遗传学 人口遗传学
- 分子进化分子进化
- 基因组学就是基因组学.
背景情况:
- 估计跨基因的选择强度是人口遗传学的长期目标.
- 现在,DNA测序和分析方法的进步使得这种估计成为可能.
- 将物种内部的遗传变异 (多态) 与物种间的差异 (分歧) 进行比较,可以发现个体基因的选择.
研究的目的:
- 为了比较Arabidopsis和Drosophila物种之间的基因替代分布.
- 研究交配系统对消除有害突变的效率的影响.
主要方法:
- 在物种之间对氨基酸替代物的比较分析.
- 利用分歧时间将多个基因的数据结合起来.
- 对比阿拉比多普西斯 (部分自我受精) 和多索菲拉 (外交) 的基因替代模式.
主要成果:
- 德洛索菲拉表现出主要是有益的基因替代.
- 阿拉比多普西斯显示主要是有害的基因替代.
- 这两种物种之间基因替代性质的显著差异.
结论:
- 与Drosophila的系统相比,Arabidopsis的部分自我受精系统在消除有害突变方面效率较低.
- 这一发现支持了种群遗传学理论,该理论将近亲繁殖与由于较小的有效种群规模而导致清除有害突变的效率降低联系在一起.
- 交配系统在塑造基因组选择格局方面发挥着至关重要的作用.
相关概念视频
01:20Monohybrid Crosses
Overview
01:18Dihybrid Crosses
Overview
01:39Test Cross
Alleles are different forms of the same gene. Humans and other diploid organisms inherit two alleles of every gene, one from each parent.
01:20Monohybrid Crosses
Overview
02:27Trihybrid Crosses
Trihybrid Crosses
Some of Mendel’s crosses examined three pairs of contrasting characteristics. Such a cross is called a trihybrid cross. A trihybrid cross is a combination of three individual monohybrid crosses. For example, plant height (tall vs. short), seed shape (round vs. wrinkled), and seed color (yellow vs. green).
The F1 generation plants of a trihybrid cross are heterozygous for all three traits and produce eight gametes. Upon self-fertilization, these gametes have an equal chance to...
Some of Mendel’s crosses examined three pairs of contrasting characteristics. Such a cross is called a trihybrid cross. A trihybrid cross is a combination of three individual monohybrid crosses. For example, plant height (tall vs. short), seed shape (round vs. wrinkled), and seed color (yellow vs. green).
The F1 generation plants of a trihybrid cross are heterozygous for all three traits and produce eight gametes. Upon self-fertilization, these gametes have an equal chance to...
01:43Incomplete Dominance
Gregor Mendel's work (1822 - 1884) was primarily focused on pea plants. Through his initial experiments, he determined that every gene in a diploid cell has two variants called alleles inherited from each parent. He suggested that amongst these two alleles, one allele is dominant in character and the other recessive. The combination of alleles determines the phenotype of a gene in an organism.