哺乳动物牙特征的不独立性
Aapo T Kangas1, Alistair R Evans, Irma Thesleff
1Developmental Biology Program, Institute of Biotechnology, PO Box 56, FIN-00014, University of Helsinki, Helsinki, Finland.
Nature
|November 13, 2004
概括
哺乳动物进化研究通常依赖于牙,但牙的特征可能不是独立的. 一个单一的基因,ectodysplasin (Eda),显著改变了小鼠的牙数量,形状和牙顶的发育,揭示了潜在的进化复杂性.
科学领域:
- 进化生物学 进化生物学
- 发展生物学 发展生物学
- 古生物学的古生物学
背景情况:
- 哺乳动物进化研究经常利用牙形态学进行遗传学分析.
- 牙特征对于理解牙是主要证据的化石种群至关重要.
- 在遗传学研究中,假设牙特征之间的独立性是常见的.
研究的目的:
- 调查牙科特征独立的发育基础.
- 为了确定一个单一的基因是否可以同时影响多个牙特征.
- 评估ectodysplasin (Eda) 信号对牙发育和形态学的影响.
主要方法:
- 在小鼠模型中操纵细胞信号蛋白ectodysplasin (Eda) 的表达水平.
- 分析牙特征的变化,包括牙顶数,形状,位置和牙数.
- 在牙冠形成过程中追踪早期发育信号中心的形态变化.
主要成果:
- 增加的ectodysplasin (Eda) 表达导致牙形态的显著变化.
- 观察到的变化包括数的增加,形状和位置的改变,纵向的形成和牙数的增加.
- 与尖端横向位置相关的字符的相关变化与早期信号中心的发展有关.
结论:
- 与常见假设相反,牙的特征可能在发育上不是独立的.
- 一个单一的基因 (Eda) 可以在牙形态的多个方面编排复杂的,相关的变化.
- 这些发现表明,牙形状的进化变化可能涉及非独立的特征修饰,如果不考虑,可能会掩盖家族遗传史.
相关概念视频
01:23Phylogeny
Phylogeny is concerned with the evolutionary diversification of organisms or groups of organisms. A group of organisms with a name is called a taxon (singular). Taxa (plural) can span different levels of the evolutionary hierarchy. For instance, the group containing all birds is a taxon (comprising the class Aves), and the group of all species of daisies (the genus Bellis) is a taxon. Phylogenies can likewise include just one genus (i.e., depict species relationships) or span an entire kingdom.
01:54Convergent Evolution
Evolution shapes the features of organisms over time, ensuring that they are suited for the environments in which they live. Sometimes, selection pressure leads to the rise of similar but unrelated adaptations in organisms with no recent common ancestors, a process known as convergent evolution.
01:15Teeth
The formation of teeth, also known as odontogenesis, is a complex process that begins in utero, around the sixth week of embryonic development. There are three stages to this process: the bud stage, the cap stage, and the bell stage.
In the bud stage, the tooth germ (an aggregation of cells) starts to form in the developing jawbone. During the cap stage, the tooth germ differentiates into enamel organ, dental papilla, and dental sac, which will later develop into the tooth's enamel, dentin and...
In the bud stage, the tooth germ (an aggregation of cells) starts to form in the developing jawbone. During the cap stage, the tooth germ differentiates into enamel organ, dental papilla, and dental sac, which will later develop into the tooth's enamel, dentin and...
01:21Tooth Anatomy
The human tooth enables us to eat a variety of foods, speak clearly, and even aid in shaping our faces. Teeth are composed of various elements that work together. Here's a detailed look at the anatomy of a human tooth.
The Crown, Neck, and Root
The visible part of the tooth is referred to as the crown. It's covered by enamel, the hardest substance in the human body. The crown is uniquely shaped for each type of tooth, allowing for different functions such as cutting, tearing, or grinding food.
The Crown, Neck, and Root
The visible part of the tooth is referred to as the crown. It's covered by enamel, the hardest substance in the human body. The crown is uniquely shaped for each type of tooth, allowing for different functions such as cutting, tearing, or grinding food.