ドロソフィラの投与量補償システムは,新しく進化したX染色体によって共用されます
I Marín1, A Franke, G J Bashaw
1Department of Biological Sciences, Stanford University, California 94305, USA.
Nature
|September 12, 1996
まとめ
ドロソフィラの用量補償は,X染色体と結合する男性特異性致死性 (MSL) タンパク質を通じて達成される. この研究は,性染色体進化とX-オートソーム転移と相関する,ドロソフィリド種間の保存されたMSL結合を明らかにしています.
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
- 分子生物学は分子生物学である.
背景:
- 投与量の補償は,異なる性染色体数を持つ種において,性に関連した遺伝子発現を均等にします.
- ドロソフィラ・メラノガスターでは,雄性特異的致死性 (MSL) タンパク質が,雄性X染色体と結合することで,投与補償を媒介する.
研究 の 目的:
- ドロソフィリド種間のMSLタンパク質結合の進化的保存を調査する.
- MSL結合パターンが性染色体の進化,特にX-オートソームの転位と相関するかどうかを判断する.
主な方法:
- ドロソフィリドの4つの属におけるMSLタンパク質結合の比較分析.
- 転位により新たに進化したX染色体腕を持つ種におけるMSL結合パターンの検討.
主要な成果:
- 3つのMSLタンパク質の性別および染色体特異的結合は,複数のドロソフィリド種に保存されています.
- MSL結合は,X-オートソーム転位の結果,特にホモログ変性後,新たに獲得されたX染色体の腕で発生する.
- ドロソフィラ・ミランダでは,ネオ-X染色体上のMSL結合パターンは,既知の投与補償領域と一致する.
結論:
- MSL媒介の用量補償は,ドロソフィラ属の保存メカニズムである.
- MSL結合は,用量補償の信頼できる指標であり,性染色体再構成と協調して進化する.
関連する概念動画
01:58X-Inactivation
The human X chromosome contains over ten times the number of genes as in the Y chromosome. Since males have only one X chromosome, and females have two, one might expect females to produce twice as many of the proteins, with undesirable results.
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.
02:45The 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...
02:50Dosage Compensation
In animals, gender is determined by the number and type of sex chromosome. For example, human females have two X chromosomes, and males have one X and one Y chromosome, whereas C.elegans with one X chromosome is a male, and the one with two X chromosomes is a hermaphrodite.
In addition to sexual development, the X chromosome has genes involved in autosomal functions such as brain development and the immune system. Therefore, males and females with distinct numbers of X chromosomes will have...
In addition to sexual development, the X chromosome has genes involved in autosomal functions such as brain development and the immune system. Therefore, males and females with distinct numbers of X chromosomes will have...
01:58X-inactivation
The human X chromosome contains over ten times the number of genes as in the Y chromosome. Since males have only one X chromosome, and females have two, one might expect females to produce twice as many of the proteins, with undesirable results.
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...