最近の人間のY染色体の共通の祖先が発見された.
1Laboratory of Molecular Systematics and Evolution, Biosciences West, University of Arizona, Tucson 85721, USA.
Nature
|November 23, 1995
まとめ
人間の起源の研究は,Y染色体が減少した変化を示していることを示しています. この研究では,最近の強い選択の証拠は見つかりませんでしたが,一般的な人間のY染色体祖先が18万8000年前に存在していたと推定されています.
科学分野:
- 人間の進化遺伝学
- 集団遺伝学 人口遺伝学
- 分子人類学は分子人類学である.
背景:
- 男性特有のY染色体は,人間の起源を追跡する上で極めて重要です.
- Y染色体における減少した核酸変異は,最近の強力な選択の可能性を示唆する.
- この減少した変異は,単一のY染色体ハプロタイプの固定に起因する可能性があります.
研究 の 目的:
- 人間のY染色体における核酸変異のパターンを調査する.
- 最近のY染色体の選択的掃描の仮説を検証するために.
- 人間のY染色体の凝結時間を推定する.
主な方法:
- 人間のY染色体とチンパンジーのY染色体の2.6キロ塩基基断片の配列解析.
- ヌクレオチド配列の多様性と分岐の分析.
- Y染色体データと自己染色体およびミトコンドリアDNA研究の比較.
主要な成果:
- 最近の人間のY染色体に強烈な選択的掃描が行われた証拠は見つかりませんでした.
- 人間のY染色体の最も最近の共通の祖先 (TMRCA) までの推定時間は188,000年 (95%CI: 51,000411,000年) である.
- この結果は,他の遺伝学研究から得られた,長期的なヒトの有効な人口規模と性別比率の推定値と一致しています.
結論:
- 観察されたY染色体変異は,最近の選択的掃描によって説明されません.
- 推定されたTMRCAは,広範囲に広がった古典的変容ではなく,最近の人間の起源のモデルをサポートしています.
- この発見は,人間の進化に関する多領域仮説の予測と矛盾している.
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