関連する実験動画
Updated: May 10, 2026

14:23
Recombineering Homologous Recombination Constructs in Drosophila
Published on: July 13, 2013
まとめ
ドロソフィラの白象変異は,タンドム複製によって引き起こされます. 精密な遺伝的逆転は,不平等なクロスオーバーではなく,染色体内再結合が主なメカニズムであることを示唆しています.
科学分野:
- * 分子遺伝学 分子遺伝学
- * ドロソフィラ・メラノガスターの研究
- * 進化的遺伝学について
背景:
- *ドロソフィラ・メラノガスターの白象牙 (wi) 変異は,白色部分の不安定なアレルである.
- *この変異は,性別とアレルの組み合わせによって異なる反転頻度を示します.
研究 の 目的:
- * ホワイト・アイボリー変異の分子基礎を解明する.
- * 白い場所の正確な遺伝的逆転の背後にあるメカニズムを調査する.
主な方法:
- * ワイルドフライのDNAの分子クローン.
- *DNAの再編成を特徴付けるためのサザンブレット分析.
- * 逆転イベントの遺伝子分析.
主要な成果:
- * 白い場所内の2.9キロベースタンデム重複が,wi変異の原因として特定されました.
- *フェノタイプの逆転は,主に重複した配列の正確な切除によるものです.
- * デリバティブアレルは,白部内の繰り返しDNAの挿入と消去を示しています.
結論:
- * 染色体内介質再結合は,正確なWi逆転の可能性のあるメカニズムであり,不平等なクロスオーバーに基づいた説明に挑戦しています.
- * 染色体内再結合は,さまざまなシステムにおけるゲノム再編成に大きく寄与する可能性があります.
- *ドロソフィラのアルレル間再結合頻度は,DNAの長さまたは同質性と直接相関しない場合があります.
関連する概念動画
Position-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.
Polytene Chromosomes
Polytene chromosomes are giant interphase chromosomes with several DNA strands placed side by side. They were discovered in the year 1881 by Balbiani in salivary glands, intestine, muscles, malpighian tubules, and hypoderm of larvae Chironomus plumosus. Hence, these are also called "Salivary gland chromosomes." These are found in insects of the order Diptera and Collembola; in certain organs of mammals; and synergids, antipodes of flowering plants. Polytene chromosomes are also regularly...
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...
Genome Copying Errors
DNA replication is a well-evolved process that copies millions of base pairs with high fidelity during each cell division. Occasionally a wrong base or a long stretch of wrong bases may get added to the daughter strands. If the errors are left unchecked, cells might accumulate several mutations that might endanger their survival. Therefore, the copying errors are checked and repaired at three levels.
Gene 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.
Exon 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...

