概括
这项研究介绍了人类α-globin伪基因 (psi alpha 1) 的核酸序列. 伪基因含有阻止蛋白质产生和改变拼接的突变,表明它是非功能性的.
科学领域:
- 分子生物学分子生物学
- 遗传学 是一个遗传学.
- 进化生物学 进化生物学
背景情况:
- 人类的α-环球蛋白基因对于氧气运输至关重要.
- 伪基因是非功能性基因拷贝,可以提供对基因演变的见解.
- 了解伪基因形成是解读基因组演变的关键.
研究的目的:
- 确定人类α-环球素假基因 (psi alpha 1) 的完整核酸序列.
- 将psi alpha 1与功能性α-globin基因 (alpha 1和alpha 2) 进行比较.
- 为了研究psi alpha 1与相邻的alpha-globin基因的进化关系.
主要方法:
- 人类α-globin假基因 (psi alpha 1) 的核酸测序.
- 在psi alpha 1和功能性人类alpha-globin基因 (alpha 1,alpha 2) 之间进行比较序列分析.
- 对功能元素的侧边区域和中间序列的分析.
主要成果:
- psi alpha 1 含有启动器密码子突变和移删除,使其无法产生α-环球蛋白多.
- 伪基因具有两种典型的哺乳动物α-globin基因的中间序列,但具有改变或缺失拼接信号.
- psi alpha1,alpha1和alpha2共享一个同源序列 (GCCTGTGTGTGCCTG) 横跨它们的多个A加法位点,这表明它们在基因复制中发挥了作用.
结论:
- 人类α-globin伪基因 (psi alpha 1) 由于关键突变和拼接缺陷而非功能性.
- 尽管存在缺陷,但特征性中间序列的存在表明它起源于功能性α-环球蛋白基因.
- 与α-环球基因重复单元接壤的同源序列可能促进了像psi alpha 1这样的伪基因的起源和进化.
相关概念视频
02:07Organization of Genes
Overview
01:57Gene Families
Gene families consist of groups of genes proposed to have originated from a common ancestor. Typically these arise through events in which a gene or genes are mistakenly duplicated during cell division. Unlike their parent genes (which are subject to selection pressure to maintain function), these gene copies do not need to preserve their sequences and may evolve at a relatively faster rate.
Occasionally these regions can be adapted to take on new roles within the organism, becoming novel genes...
Occasionally these regions can be adapted to take on new roles within the organism, becoming novel genes...
02:47Protein Families
Protein families are groups of homologous proteins; that is, they have similarities in amino acid sequences and three-dimensional structures. Protein families usually occur because of gene duplication, where an additional copy of a gene is inserted into the genome of an organism. Mutations that change the amino acids but still allow the protein to be properly synthesized, will lead to new protein family members. If these new proteins contain similar amino acids in key locations, protein...
02:37Gene Duplication and Divergence
The seminal work of Ohno in 1970 popularized the idea of gene duplication and divergence. DNA sequence comparison studies reveal that a large portion of the genes in bacteria, archaebacteria, and eukaryotes was generated by gene duplication and divergence, indicating its critical role in evolution.
The duplicated copies of the gene are called Paralogs. Paralogs with similar sequences and functions form a gene family. Across several species, a large number of gene families are characterized.
The duplicated copies of the gene are called Paralogs. Paralogs with similar sequences and functions form a gene family. Across several species, a large number of gene families are characterized.
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...
02:05Duplication of Chromatin Structure
The process of chromosome duplication during cell division requires genome-wide disruption and re-assembly of chromatin. The chromatin structure must be accurately inherited, reassembled, and maintained in the daughter cells to ensure lineage propagation.
The basic unit of the chromatin is the nucleosome, consisting of DNA wrapped around octameric histone proteins and short stretches of linker DNA separating individual nucleosomes. The histone proteins within the nucleosome have their...
The basic unit of the chromatin is the nucleosome, consisting of DNA wrapped around octameric histone proteins and short stretches of linker DNA separating individual nucleosomes. The histone proteins within the nucleosome have their...