昆虫のパターンの形成の進化の過程で,Even-skippedの役割が変化した
N H Patel1, E E Ball, C S Goodman
1Howard Hughes Medical Institute, Department of Molecular and Cell Biology, University of California, Berkeley 94720.
Nature
|May 28, 1992
まとめ
昆虫の発達は,長生殖帯 (ドロソフィラ) と短生殖帯 () のモードによって異なります. ドロソフィラのセグメンテーションに不可欠な"even-skipped"遺伝子は,のペアルール遺伝子として機能せず,異なる発達経路を示している.
科学分野:
- 発達生物学 発達生物学とは
- 進化的発達生物学 進化的発達生物学
- 遺伝学 遺伝学とは
背景:
- 昆虫の発達には,長い生殖帯 (例えば,ドロソフィラ) と短い生殖帯 (例えば,) を含む多様なモードがあります.
- セグメントパターンの確立は,分子レベルで観察可能なこれらのモードの間で著しく異なります.
- セグメントの極性遺伝子とホメオティック遺伝子の腹部-Aは,ゲルムバンドタイプに関連した明確な発現パターンを示しています.
研究 の 目的:
- 昆虫の生殖帯の発達における差異の分子基盤を調査する.
- の発達における,even-skipped遺伝子同類体の機能を特徴づけるために.
- 昆虫群の早期のセグメンテーションと後の神経生成における偶跳びの役割を比較する.
主な方法:
- ドロソフィラ・ペア・ルールの遺伝子のトカゲの同類のクローニング. 均等にスキップ.
- 胚の発達中の遺伝子発現パターンの比較分析.
- セグメンテーションとニューロゲネシスにおけるEven-Skippedの役割を評価する機能的研究.
主要な成果:
- のEven-Skippedホモローグは,胚の初期セグメンテーション中にペアルール遺伝子として機能しません.
- ドロソフィラと違って,ヒョウヒョウの偶数スキップ表現は,最初のペアルールパターンを確立しません.
- 均等にスキップされた遺伝子は,ドロソフィラとの両方のニューロゲネシスで保存された機能を保持しています.
結論:
- 偶跳びのペアルール機能は,ドロソフィラのような長生殖帯昆虫に特異的です.
- 短生殖帯の昆虫は,早期のセグメンテーションのために代替的な分子機構を使用します.
- 初期の発達における差異にもかかわらず,神経生成のような後の発達過程において,even-skippedの役割は保存されています.
関連する概念動画
01:07Speciation Rates
Speciation can proceed at markedly different rates, and evolutionary biologists commonly describe these differences through the models of gradualism and punctuated equilibrium. Both patterns explain how new species arise, but they differ in the tempo and continuity of evolutionary change. In both cases, evolutionary change arises from heritable variation within populations, with natural selection often shaping traits that improve survival and reproduction under specific environmental conditions.
01:32What is Natural Selection?
Natural selection is an evolutionary process in which individuals with survival-promoting traits reproduce at higher rates. These favorable traits become more common within a population or species. Naturally selected traits initially arise via random genetic mutations. In order for selection to occur, there must be variation within a population, the trait controlling the variation must be heritable, and there must be an evolutionary advantage for variation in the trait.The Theory of Natural...
01:09Mutation, Gene Flow, and Genetic Drift
In a population that is not at Hardy-Weinberg equilibrium, the frequency of alleles changes over time. Therefore, any deviations from the five conditions of Hardy-Weinberg equilibrium can alter the genetic variation of a given population. Conditions that change the genetic variability of a population include mutations, natural selection, non-random mating, gene flow, and genetic drift (small population size).Mechanisms of Genetic VariationThe original sources of genetic variation are mutations,...
01:38Limits to Natural Selection
Organisms that are well-adapted to their environment are more likely to survive and reproduce. However, natural selection does not lead to perfectly adapted organisms. Several factors constrain natural selection.For one, natural selection can only act upon existing genetic variation. Hypothetically, redtusks may enhance elephant survival by deterring ivory-seeking poachers. However, if there are no gene variants—or alleles—for redtusks, natural selection cannot increase the prevalence of...
03:33Genetic Drift
Natural selection—probably the most well-known evolutionary mechanism—increases the prevalence of traits that enhance survival and reproduction. However, evolution does not merely propagate favorable traits, nor does it always benefit populations.Life is not fair. A deer grazing contentedly in a field can have her meal cut tragically short by a bolt of lightning. If the doomed doe is one of only three in the population, 1/3 of the population’s gene pool is lost. Random events like this can...
01:24Evolution of New Traits in Microbes
Microorganisms evolve rapidly due to their large population sizes and short generation times, often exhibiting measurable changes within days under laboratory conditions. Natural selection acts on standing genetic variation, enabling the retention and amplification of beneficial traits that confer fitness advantages in changing environments.Adaptive Pigment Regulation in RhodobacterIn Rhodobacter, a genus of purple non-sulfur bacteria, light-harvesting pigments such as bacteriochlorophyll and...