概括
高度多态基因,如小鼠主要基因相容性位点,显示基因转换的证据. 这项研究表明,这些系统中的基因转化事件最多发生在雌性性体形成过程中.
科学领域:
- 遗传学 是一个遗传学.
- 免疫学 免疫学 免疫学
- 分子生物学分子生物学
背景情况:
- 高度多态的基因位点,如免疫球蛋白基因和脊椎动物主要基因相容性位点,存在独特的进化挑战.
- 这种广泛的遗传变异的起源和维持尚未完全理解,但怀疑有专门的机制.
- 小鼠H-2类I主要基因相容性位是高度多态化的研究良好的例子,其变异性集中在特定的基因区域.
研究的目的:
- 调查导致H-2类I主要基因相容性位点中观察到的高多态的机制.
- 为了确定基因转换事件的起源,怀疑在产生H-2多态化中发挥作用.
- 分析突变的H-2等位基因,以了解这种高度变化的系统中基因转换的过程.
主要方法:
- 突变I类H-2等位基因的序列分析.
- 对DNA序列进行检查,以寻找相邻部位的协同变化的证据,表明基因转换.
- 对经过基因转换的基因位置的染色体起源的分析.
主要成果:
- 对H-2突变的序列分析为I类基因中基因转换事件提供了有力的证据.
- 这些基因转换事件涉及相邻DNA位点的协调变化,表明与相关位点的重组.
- 分析表明,染色体含有经历基因转换的位置源自雌性小鼠.
结论:
- 基因转换是一个重要的机制,有助于H-2类I主要基因相容性位点的高多态性.
- 哺乳动物中介基因转换在雌性性生殖过程中表现出明显的偏好,而不是男性性生殖过程中.
- 这一发现揭示了在高度多态系统中塑造遗传多样性的进化过程.
相关概念视频
01:16In-vitro Mutagenesis
To learn more about the function of a gene, researchers can observe what happens when the gene is inactivated or “knocked out,” by creating genetically engineered knockout animals. Knockout mice have been particularly useful as models for human diseases such as cancer, Parkinson’s disease, and diabetes.
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.
02:08Gene Conversion
Other than maintaining genome stability via DNA repair, homologous recombination plays an important role in diversifying the genome. In fact, the recombination of sequences forms the molecular basis of genomic evolution. Random and non-random permutations of genomic sequences create a library of new amalgamated sequences. These newly formed genomes can determine the fitness and survival of cells. In bacteria, homologous and non-homologous types of recombination lead to the evolution of new...
02:32Exon Recombination
The evolution of new genes is critical for speciation. Exon recombination, also known as exon shuffling or domain shuffling, is an important means of new gene formation. It is observed across vertebrates, invertebrates, and in some plants such as potatoes and sunflowers. During exon recombination, exons from the same or different genes recombine and produce new exon-intron combinations, which might evolve into new genes.
Exon shuffling follows “splice frame rules.” Each exon has three reading...
Exon shuffling follows “splice frame rules.” Each exon has three reading...
02:43Mouse Models of Cancer Study
Mice have long served as models for studying human biology and pathology because of their phylogenetic and physiological similarity with humans. They are also easy to maintain and breed in the laboratory, and hence, many inbred strains are now available for research. Studies on mice have contributed immeasurably to our understanding of cancer biology.
The development of transgenic, knockout, and knock-in mice has led to an exponential increase in their use as model organisms in research,...
The development of transgenic, knockout, and knock-in mice has led to an exponential increase in their use as model organisms in research,...
02:08Gene Conversion
Other than maintaining genome stability via DNA repair, homologous recombination plays an important role in diversifying the genome. In fact, the recombination of sequences forms the molecular basis of genomic evolution. Random and non-random permutations of genomic sequences create a library of new amalgamated sequences. These newly formed genomes can determine the fitness and survival of cells. In bacteria, homologous and non-homologous types of recombination lead to the evolution of new...