玉米的遗传特性 嵌套协会绘制人口的图谱
Michael D McMullen1, Stephen Kresovich, Hector Sanchez Villeda
1United States Department of Agriculture-Agriculture Research Service (USDA-ARS), USA. mcmullenm@missouri.edu
Science (New York, N.Y.)
|August 8, 2009
概括
玉米的遗传多样性表明,局部DNA变异会影响重组率. 具有较低重组的围心层区域可能会对玉米异质有显著的贡献.
科学领域:
- 植物遗传学 植物遗传学
- 农业科学 农业科学
- 分子生物学分子生物学
背景情况:
- 玉米的遗传多样性对于理解表型变异和提高作物改进以提高农业效率和可持续性至关重要.
- 以前的研究已经利用玉米的遗传多样性来探索特征的分子基础,并优化农业实践.
研究的目的:
- 调查局部遗传变异在影响玉米重组频率中的作用.
- 评估重组率对遗传多样性,链接不平衡和分离扭曲的影响.
- 探索重组,选择效率和异构在周周中心区域之间的关系.
主要方法:
- 通过与B73参考线交叉25个不同的杂交玉米线.
- 分析了大约1.36万个重组事件,以确定重组频率的变化.
- 评估单位效应,双位点连接不平衡和分离扭曲.
- 检查周心区域的残留异性,以推断选择效率.
主要成果:
- 在玉米家族中观察到重组频率的显著变化,受当地 (cis) 遗传变异的影响.
- 确定了许多小单位效应,对大效应基因或影响健康的表观相互作用的证据有限.
- 在周心区域发现了多余的残留异性,这表明由于这些区域的重组率较低,选择效率降低.
结论:
- 当地遗传变异在调节玉米的重组频率方面发挥着关键作用.
- 在内杂玉米系的低再组合的周心区域中,选择效率较低.
- 由于再组合减少,周中心区域可能会不成比例地导致玉米的异质化.
相关概念视频
01:18Dihybrid Crosses
Overview
01:20Monohybrid Crosses
Overview
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...
02:03Law of Independent Assortment
While Mendel’s Law of Segregation states that the two alleles for one gene are separated into different gametes, a different question of how different genes are inherited remains. For example, is the gene for tall plants inherited with the gene for green peas? Mendel asked this question by experimenting with a dihybrid cross; a cross in which both parents are homozygous for two distinct traits resulting in an F1 generation that are heterozygous for both traits.
02:46Chi-square Analysis
The chi-square test is a statistical hypothesis test. It is used to check whether there is a significant difference between an expected value and an observed value. In the context of genetics, it enables us to either accept or reject a hypothesis, based on how much the observed values deviate from the expected values.
The chi-square test was developed by Pearson in 1990.
The first step of performing a Chi-square analysis is to establish a null hypothesis, which assumes that there is no real...
The chi-square test was developed by Pearson in 1990.
The first step of performing a Chi-square analysis is to establish a null hypothesis, which assumes that there is no real...