蝶の眼球の定量的な変動に対するディスタルレスの貢献度
Patrícia Beldade1, Paul M Brakefield, Anthony D Long
1Institute of Evolutionary and Ecological Sciences, University of Leiden, PO Box 9516, 2300 RA Leiden, The Netherlands. pbeldade@rulsfb.leidenuniv.nl
Nature
|January 18, 2002
まとめ
蝶の翼の色彩パターンは,進化と発達の研究の鍵です. 研究者らは,Bicyclus anynana蝶のディスタルレス遺伝子のDNA変異とアイスポットサイズとの関連性を発見した.
科学分野:
- 進化的発達生物学 進化的発達生物学
- 遺伝学 遺伝学とは
- 動物の色付け 動物の色付け
背景:
- バタフライの翼の色パターン,特にアイスポットは,進化の選択と発達過程の相互作用を研究するための優れたモデルです.
- 熱帯の蝶Bicyclus anynanaは,その定量可能な形態学的多様性のために,アイスポット研究のための焦点種です.
- 発達経路が眼球形成に関与している一方で,定量的な変化を誘発する特定の遺伝子は未確認のままである.
研究 の 目的:
- 遺伝的多様性を蝶の翼パターンの進化と結びつけるために.
- Bicyclus anynanaの眼球形態の定量的な変化に寄与する特定の遺伝子を特定する.
- 翼パターンの進化の研究と発達中の遺伝子発現の研究の間のギャップを埋めるために.
主な方法:
- 関連する発達経路内の候補遺伝子のDNAポリモルフィズムを調査した.
- 付属体の発達に重要な役割を果たすディスタルレス (Dll) 遺伝子に焦点を当てた.
- Dllの遺伝子変異とB. anynanaのアイスポットサイズとの関連を分析した.
主要な成果:
- Distal-less (Dll) 遺伝子のDNAポリモルフィズムと眼球サイズの変化との間に有意な関連性を示した.
- 特定の遺伝子を蝶の翼の特徴の定量的な変化と結びつける最初の遺伝的証拠を提供した.
- アイスポット形態学の適応的進化に影響を与える候補遺伝子としてDllを特定しました.
結論:
- Distal-less (Dll) 遺伝子は,眼球の大きさの定量的な変動に寄与する可能性が高いので,自然選択のターゲットになります.
- この研究は,進化的発達生物学の文脈で,遺伝子型とフェノタイプの間の重要なリンクを提供します.
- これからの研究は,これらの発見に基づいて,複雑な適応性特性の遺伝的構造を明らかにすることができます.
関連する概念動画
01:21Frequency-dependent Selection
When the fitness of a trait is influenced by how common it is (i.e., its frequency) relative to different traits within a population, this is referred to as frequency-dependent selection. Frequency-dependent selection may occur between species or within a single species. This type of selection can either be positive—with more common phenotypes having higher fitness—or negative, with rarer phenotypes conferring increased fitness.
02:32Position-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.
02:27Background and Environment Affect Phenotype
Although the genetic makeup of an organism plays a major role in determining the phenotype, there are also several environmental factors, such as temperature, oxygen availability, presence of mutagens, that can alter an organism’s phenotype.
An example of how genetic background affects phenotype can be seen in horses. The Extension gene in horses is responsible for their coat color. A wild-type gene (EE) produces black pigment in the coat, while a mutant gene (ee) produces red pigment. A...
An example of how genetic background affects phenotype can be seen in horses. The Extension gene in horses is responsible for their coat color. A wild-type gene (EE) produces black pigment in the coat, while a mutant gene (ee) produces red pigment. A...
01:21Testing a Claim about Mean: Unknown Population SD
A complete procedure of testing a hypothesis about a population mean when the population standard deviation is unknown is explained here.
Estimating a population mean requires the samples to be approximately normally distributed. The data should be collected from the randomly selected samples having no sampling bias. There is no specific requirement for sample size. But if the sample size is less than 30, and we don't know the population standard deviation, a different approach is used; instead...
Estimating a population mean requires the samples to be approximately normally distributed. The data should be collected from the randomly selected samples having no sampling bias. There is no specific requirement for sample size. But if the sample size is less than 30, and we don't know the population standard deviation, a different approach is used; instead...