無性性への移行は,過剰なアミノ酸置換を引き起こします
Susanne Paland1, Michael Lynch
1Department of Biology, Indiana University, 1001 East 3rd Street, Bloomington, IN 47405, USA. spaland@indiana.edu
まとめ
無性繁殖は,ミトコンドリア遺伝子の有害な突然変異の蓄積を加速する. 性繁殖は,これらの変異を排除し,遺伝的健康を維持するために不可欠です.
科学分野:
- 進化生物学の進化生物学について
- 遺伝学 遺伝学とは
- 分子生物学は分子生物学である.
背景:
- 遺伝的リンクは,浄化選択の有効性を損なう可能性があります.
- 永久にリンクされた遺伝子を持つ無性系は,核および臓器DNAに有害な突然変異を蓄積する可能性があります.
研究 の 目的:
- ミトコンドリアのタンパク質をコードする遺伝子における突然変異の蓄積に対する無性繁殖の影響を調査する.
- 無性系と性系間の有害なアミノ酸置換率を比較する.
主な方法:
- ミトコンドリアのタンパク質コード遺伝子のアミノ酸と静かな置換率 (Ka/Ks) の比率を分析した.
- 変異の影響を分類し,定量化するために, fylogeny ベースのアプローチを使用しました.
主要な成果:
- 強制的に無性であるダフニア・プルレックス系は,性系と比較して,ミトコンドリア遺伝子のKa/Ks比率が高かった.
- 無性系におけるミトコンドリア遺伝子は,有害なアミノ酸の置換を,性系で観察された割合のおよそ4倍に蓄積する.
結論:
- 性繁殖は,集団内の突然変異の負荷を軽減する上で重要な役割を果たします.
- 無性繁殖は,特にミトコンドリアゲノムにおける有害な突然変異の蓄積を悪化させる.
関連する概念動画
Mutations
Overview
Urea Cycle
The urea cycle describes how liver cells convert ammonia to urea. Ammonia is a toxic waste product of protein catabolism. Land animals must convert ammonia into the less toxic urea which can be safely eliminated by the kidneys through urine. Marine animals excrete ammonia directly, and the surrounding water dilutes the ammonia to safe levels.
Comparative Excretory Systems
Animals have evolved different strategies for excretion, the removal of waste from the body. Most waste must be dissolved in water to be excreted, so an animal’s excretory strategy directly affects its water balance.
Overview of Nitrogen Metabolism
Nitrogen is a very important element for life because it is a major constituent of proteins and nucleic acids. It is a macronutrient, and in nature, it is recycled from organic compounds and stored in the form of ammonia, ammonium ions, nitrate, nitrite, or nitrogen gas by many metabolic processes. Many of these metabolic processes are carried out only by prokaryotes.
The largest pool of nitrogen available in the terrestrial ecosystem is gaseous nitrogen (N2) from the air, but this nitrogen...
The largest pool of nitrogen available in the terrestrial ecosystem is gaseous nitrogen (N2) from the air, but this nitrogen...
Mutations
Mutations are changes in the sequence of DNA. These changes can occur spontaneously or they can be induced by exposure to environmental factors. Mutations can be characterized in a number of different ways: whether and how they alter the amino acid sequence of the protein, whether they occur over a small or large area of DNA, and whether they occur in somatic cells or germline cells.
Chromosomal Alterations Are Large-Scale Mutations
While point mutations are changes in a single nucleotide in...
Chromosomal Alterations Are Large-Scale Mutations
While point mutations are changes in a single nucleotide in...
Amino Acid Catabolism
Microorganisms rely on proteins as an essential carbon and energy source, particularly in environments with limited polysaccharides or lipids. However, proteins are too large to cross the plasma membrane unaided, necessitating enzymatic degradation. Microbes secrete extracellular proteases and peptidases that hydrolyze proteins into peptides, which can then be transported across the membrane. Once inside the cell, intracellular proteases degrade these peptides into free amino acids, which...


