在基因学背景下,重新审视非哺乳动物突触体中的哺乳动物下的进化趋势
Tomohiro Harano1, Masakazu Asahara1
1Division of Liberal Arts and Sciences, Aichi Gakuin University, Nisshin, Aichi, Japan.
PeerJ
|June 26, 2023
概括
哺乳动物下是通过牙骨的垂直扩张进化而形成的,而不是灭绝的类动物的一般扩张趋势. 这表明独特的哺乳动物下结构有着不同的进化路径.
科学领域:
- 古生物学的古生物学
- 进化生物学 进化生物学
- 比较解剖学的比较解剖学
背景情况:
- 哺乳动物下由单一的牙骨组成,与它们灭绝的非哺乳动物突触体祖先不同,它们有多个骨头.
- 以前的研究表明,非哺乳动物突触类动物的牙扩大和牙后骨缩小趋势,但这缺乏现代遗传学验证.
研究的目的:
- 在非哺乳动物同类动物中,使用基因组比较方法研究牙大小与下整体相对的进化模式.
- 为了确定是否存在牙扩大的持续趋势,以牺牲牙后骨头为代价.
主要方法:
- 来自各种非哺乳动物突触体种群的测量结果的遗传学分析.
- 检查牙大小相对于下在侧面视图 (面积) 和前后维度.
- 祖先的角色重建,以了解进化途径.
主要成果:
- 在非哺乳动物的突触类动物中,在侧向视图中观察到与下相对较大的牙区域扩大的显著进化趋势.
- 这种扩大似乎主要是由于牙的垂直扩张.
- 没有发现牙扩大以牺牲牙后骨为代价的持续趋势,进化模式并不严格单向.
结论:
- 哺乳动物单牙下巴的进化并不能完全由祖先形式中牙扩大的简单,持续的趋势来解释.
- 独特的哺乳动物部结构很可能是由于在从非哺乳动物 cynodonts 到早期哺乳动物的特定过渡期间的选择压力而产生的.
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