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Recombineering Homologous Recombination Constructs in Drosophila
Published on: July 13, 2013
アフリカ系アメリカ人における再結合の風景
Anjali G Hinch1, Arti Tandon, Nick Patterson
1Wellcome Trust Centre for Human Genetics, Oxford University, Roosevelt Drive, Oxford OX3 7BN, UK.
Nature
|July 22, 2011
まとめ
遺伝子の再組み合わせによって,多様性が生まれます. 研究者は,アフリカ系アメリカ人におけるヒトのクロスオーバー率をマッピングし,PRDM9遺伝子と独特のDNAモチーフの影響を受けた集団特有の再結合ホットスポットを明らかにしました.
科学分野:
- 遺伝学 遺伝学とは
- 人間の進化 人類の進化
- 人口遺伝学 人口遺伝学
背景:
- 遺伝的多様性は,集団の進化において極めて重要です.
- 再結合と突然変異は,遺伝的多様性の主要な原動力である.
- アメリカ大陸での最近の添加物は,再結合パターンを研究するためのユニークな機会を提供します.
研究 の 目的:
- ヒトゲノムにおける再結合率の高解像度遺伝子マップを構築する.
- アフリカとヨーロッパの祖先の集団間の再結合パターンの違いを特定する.
- クロスオーバーの位置を制御するPRDM9遺伝子の役割を調査する.
主な方法:
- 約210万台のクロスオーバーを分析した結果,関係のないアフリカ系アメリカ人3万人を対象としたものです.
- アフリカ系アメリカ人とヨーロッパ人の再結合地図の比較.
- 再結合ホットスポットに関連したDNA配列モチーフの識別と特徴付け.
主要な成果:
- 人間のクロスオーバー確率の詳細な遺伝子マップが作成されました.
- 集団間の微細なゲノムスケールでは,再結合パターンの有意な違いが観察されました.
- 西アフリカの祖先集団で活動している約2,500の再結合ホットスポットが特定され,大部分はヨーロッパ人に不活性であった.
- PRDM9遺伝子アレルは,これらのホットスポットでのクロスオーバー活動を強く制御することが判明しました.
- PRDM9結合標的と一致する17塩基対のDNAモチーフは,これらのホットスポットで濃縮された.
結論:
- この研究は,ヒトの遺伝的多様性と進化を理解するための貴重なリソースを提供します.
- 集団特有の再結合パターン,特にホットスポットは,PRDM9アレルおよび関連するDNAモチーフの影響を受けます.
- これらの発見は,ゲノム再編成に関連した疾患リスクの位置を特定するための意味を持つ.
関連する概念動画
Conservative Site-specific Recombination and Phase Variation
Because the DNA segments are cut and reorganized in a direction-specific manner, site-specific recombination has emerged as an efficient genetic engineering technique. Flippase and Cyclization recombinases or Flp and Cre, respectively, are two members of the tyrosine recombinase family derived from bacteriophages, that are used to mediate site-specific DNA insertions, deletions, and targeted expression of proteins in mammalian cell lines.
The recognition sites for Cre recombinase called LoxP...
The recognition sites for Cre recombinase called LoxP...
Crossing Over
Crossing over is the exchange of genetic information between homologous chromosomes during prophase I of meiosis I. Genetic recombination gives rise to allelic diversity in the newly formed daughter cells. In humans, crossing over produces genetically distinct haploid egg and sperm cells that undergo fertilization to produce unique offspring. Before cell division starts, the germ cell’s chromosome(s) undergo duplication in the S phase of the cell cycle. As the cells enter prophase I, duplicated...
Crossing Over
Unlike mitosis, meiosis aims for genetic diversity in its creation of haploid gametes. Dividing germ cells first begin this process in prophase I, where each chromosome—replicated in S phase—is now composed of two sister chromatids (identical copies) joined centrally.
The homologous pairs of sister chromosomes—one from the maternal and one from the paternal genome—then begin to align alongside each other lengthwise, matching corresponding DNA positions in a process called synapsis.
In order to...
The homologous pairs of sister chromosomes—one from the maternal and one from the paternal genome—then begin to align alongside each other lengthwise, matching corresponding DNA positions in a process called synapsis.
In order to...
Overview of Transposition and Recombination
Transposons make up a significant part of genomes of various organisms. Therefore, it is believed that transposition played a major evolutionary role in speciation by changing genome sizes and modifying gene expression patterns. For example, in bacteria, transposition can lead to conferring antibiotic resistance. Movement of transposable elements within the genetic pool of pathogenic bacteria can aid in transfer of antibiotic-resistant genetic elements. In eukaryotes, transposons can carry out...
Homologous Recombination
The basic reaction of homologous recombination (HR) involves two chromatids that contain DNA sequences sharing a significant stretch of identity. One of these sequences uses a strand from another as a template to synthesize DNA in an enzyme-catalyzed reaction. The final product is a novel amalgamation of the two substrates. To ensure an accurate recombination of sequences, HR is restricted to the S and G2 phases of the cell cycle. At these stages, the DNA has been replicated already and the...
Homologous Recombination
The basic reaction of homologous recombination (HR) involves two chromatids that contain DNA sequences sharing a significant stretch of identity. One of these sequences uses a strand from another as a template to synthesize DNA in an enzyme-catalyzed reaction. The final product is a novel amalgamation of the two substrates. To ensure an accurate recombination of sequences, HR is restricted to the S and G2 phases of the cell cycle. At these stages, the DNA has been replicated already and the...
