概括
多虫的白色位控制着眼睛的颜色. 发现一种特定的突变,白色红色,是由DNA插入引起的,并且通过移除这种插入,其逆转恢复了正常的眼睛颜色.
科学领域:
- 遗传学 是一个遗传学.
- 分子生物学分子生物学
- 发展生物学 发展生物学
背景情况:
- 在Drosophila melanogaster中,白色的位置对于正常的眼睛色素来说至关重要,突变会导致改变眼睛颜色.
- 白色红色 (wc) 基因组是白色象牙 (wi) 基因组的部分逆转基因,其中包括白色基因组内的重复.
研究的目的:
- 为了阐明Drosophila中白色色 (wc) 基因的分子基础.
- 了解WC等位基因对野生类型和白象牙 (wi) 现型的高频逆转背后的机制.
主要方法:
- 分子克隆和南方斑点分析来自白色等位基因的基因组DNA.
- 对白色色等位基因的独立表型逆转基因的分析.
主要成果:
- 白色红色 (wc) 类型的表型来自于将10基基基基因序列插入白色象 (wi) 复制体中的白色基位.
- 回归白象牙 (wi) 现型需要精确切除10 kb插入.
- 回归野生类型的表型包括切除插入和wi复制的一副本,恢复原始基因结构.
结论:
- 白色的结构和功能在Drosophila可以通过DNA插入和重复显著地改变.
- 插入序列的切除和重复是白色位点中恢复到野生类型或中间表型的关键机制.
- 这项研究提供了详细的分子洞察力,了解了白色位点基因突变和逆转的动态性质.
相关概念视频
01:39Epistasis
In addition to multiple alleles at the same locus influencing traits, numerous genes or alleles at different locations may interact and influence phenotypes in a phenomenon called epistasis. For example, rabbit fur can be black or brown depending on whether the animal is homozygous dominant or heterozygous at a TYRP1 locus. However, if the rabbit is also homozygous recessive at a locus on the tyrosinase gene (TYR), it will have an unshaded coat that appears white, regardless of its TYRP1...
02:32Position-effect Variegation
In 1928, a German botanist Emil Heitz observed the moss nuclei with a DNA binding dye. He observed that while some chromatin regions decondense and spread out in the interphase nucleus, others do not. He termed them euchromatin and heterochromatin, respectively. He proposed that the heterochromatin regions reflect a functionally inactive state of the genome. It was later confirmed that heterochromatin is transcriptionally repressed, and euchromatin is transcriptionally active chromatin.
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.
02:41Lethal Alleles
Agouti: A Lethal Allele
Lucien Cuénot discovered lethal alleles in 1905 while studying the inheritance of coat color in mice. The agouti gene is responsible for the color of the coat in mice. This gene codes for an agouti-signaling protein, which is responsible for melanin distribution in mammals. The wild-type allele gives rise to gray-brown coat color in mice, while the mutant allele gives rise to yellow coat color. In addition to coat color, the agouti gene is associated with the yellow...
Lucien Cuénot discovered lethal alleles in 1905 while studying the inheritance of coat color in mice. The agouti gene is responsible for the color of the coat in mice. This gene codes for an agouti-signaling protein, which is responsible for melanin distribution in mammals. The wild-type allele gives rise to gray-brown coat color in mice, while the mutant allele gives rise to yellow coat color. In addition to coat color, the agouti gene is associated with the yellow...
02:45The Ratio of X Chromosome to Autosomes
In most organisms, sex is determined by the ratio of X and Y chromosomes. However, in some organisms, such as Drosophila and C.elegans, sex is determined by the ratio of the number of X chromosomes to the number of sets of autosomes. The Y chromosome in Drosophila is active but does not determine sex. It contains genes responsible for the production of sperms in adult flies.
Normal male Drosophila has a ratio of one X chromosome to two sets of autosomes. In contrast, normal female Drosophila...
Normal male Drosophila has a ratio of one X chromosome to two sets of autosomes. In contrast, normal female Drosophila...
00:49Complementation Tests
A complementation test is a simple cross to identify whether the two mutations are located on the same gene or different genes. It was first performed by Edward Lewis in the 1940s while working on fruit flies. He developed the test to identify the location and arrangement of different mutations on chromosomes.
Organisms heterozygous for different mutations are crossed pairwise in all combinations. If present on different genes, the mutations can complement each other by providing the missing...
Organisms heterozygous for different mutations are crossed pairwise in all combinations. If present on different genes, the mutations can complement each other by providing the missing...