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性別決定とY染色体の進化:袋類におけるSRY関連配列
J W Foster1, F E Brennan, G K Hampikian
1Department of Genetics and Human Variation, La Trobe University, Bundoora, Victoria, Australia.
Nature
|October 8, 1992
まとめ
科学者たちは,2種類の有袋動物のY染色体上にあるSRY遺伝子ホモローグを特定した. これらの発見は,HMGボックスの外にあるSRY遺伝子の急速な進化を明らかにし,哺乳類の性別決定に関する洞察を提供します.
科学分野:
- 遺伝学 遺伝学とは
- 進化生物学の進化生物学について
- 哺乳類の繁殖 哺乳類の繁殖
背景:
- 哺乳類の性別決定は,主にY染色体による丸決定因子によって制御されます.
- 人間のY染色体で確認されたSRY (Sex-determining Region Y) 遺伝子は,ヒトとマウスの主な丸決定因子と考えられています.
研究 の 目的:
- 2種類の有袋動物のY染色体からSRYに関連する遺伝子を特定し,クローン化する.
- ユーテリアン (胎盤) とメタテリアン (魚介類) のY位置のSRY配列を比較して,その進化パターンを理解する.
主な方法:
- ヒトのSRY遺伝子プローブを使用して,同種の遺伝子を識別し,クローン化しました.
- 2種類の異なる有袋動物のY染色体に焦点を当てました.
- エウテリアンとメタテリアンSRY遺伝子の配列比較を行った.
主要な成果:
- 研究された有袋類のY染色体からSRY同種を成功裏に特定し,クローン化しました.
- 配列の比較は,SRY遺伝子の急速な進化的変化を示し,特にDNA結合のHMGボックスの外にある領域を示した.
- SRYホモロゴは,Ube1yホモロゴと共に,袋鼠Y染色体で最初に識別された遺伝子を表しています.
結論:
- この研究は,Y染色体遺伝子を marsupials,特にSRYの同類種で初めて特定しました.
- 証拠は,哺乳類の系統,特にHMG以外のボックスドメインでSRY遺伝子の加速進化を示唆しています.
- これらの発見は,哺乳類の性別決定の分子メカニズムと進化の動態を理解するのに寄与しています.
関連する概念動画
Pedigree Analysis
Overview
X-linked Traits
In most mammalian species, females have two X sex chromosomes and males have an X and Y. As a result, mutations on the X chromosome in females may be masked by the presence of a normal allele on the second X. In contrast, a mutation on the X chromosome in males more often causes observable biological defects, as there is no normal X to compensate. Trait variations arising from mutations on the X chromosome are called “X-linked”.
X and Y Chromosomes
Among mammals, the gender of an organism is determined by the sex chromosomes. Humans have two sex chromosomes, X and Y. Every human diploid cell has 22 pairs of autosomes and one pair of sex chromosomes. A human female has two X chromosomes, while a male has one X chromosome and one Y chromosome.
The germline cells such as egg and sperm cells carry only half the number of chromosomes, i.e., 22 autosomes and one sex chromosome. All eggs have an X chromosome, while sperm cells can carry an X or...
The germline cells such as egg and sperm cells carry only half the number of chromosomes, i.e., 22 autosomes and one sex chromosome. All eggs have an X chromosome, while sperm cells can carry an X or...
The Y Chromosome Determines Maleness
The Y chromosome is a sex chromosome found in several vertebrates and mammals, including humans. In addition to 22 pairs of autosomes, the human males have one X chromosome and one Y chromosome. In these organisms, the presence or absence of the Y chromosome determines the development of male traits.
Evolution
Around 300 million years ago, the two sex chromosomes diverged from two identical autosomal chromosomes. Over time, the Y chromosome has lost most of its genes, shrinking in size. Today,...
Evolution
Around 300 million years ago, the two sex chromosomes diverged from two identical autosomal chromosomes. Over time, the Y chromosome has lost most of its genes, shrinking in size. Today,...
The 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...
X-linked Traits
In most mammalian species, females have two X sex chromosomes and males have an X and Y. As a result, mutations on the X chromosome in females may be masked by the presence of a normal allele on the second X. In contrast, a mutation on the X chromosome in males more often causes observable biological defects, as there is no normal X to compensate. Trait variations arising from mutations on the X chromosome are called “X-linked”.

