The origin and diversification of human temperature sensory receptors.

动物通过感官系统中的感受器来感知环境中的物理化学波动。温度传感器能够在广泛的温度范围内检测和区分刺激。这些传感器是瞬时受体电位(Trp)家族的三个亚家族(Trp V、TRPM和TRPA)的成员。在这个项目中，有两个目的：1)推测这些温度受体的分子进化；2)阐明人类温度感受器多样性的起源。1)脊椎动物温度受体的分子进化：在陆生动物基因组中发现了比在鱼类基因组中更多的Trp同源基因，反映了环境中温度波动的不同程度。在哺乳动物中，有九个温度感觉受体基因，其中四个(TRPV1‘4)负责感觉热或热。对脊椎动物TRPV1-4基因的系统发育研究表明，在鸟类和哺乳动物的干谱系中，每个TRPV基因都有过多的氨基酸替换，这表明要么替代速度加快，要么收敛进化频繁发生。这些替换可能与温血动物体温控制系统的发展有关。2)人类温度感受器多样性的起源：在NCBI记录中，有TRPV1假基因的记录。为了研究这种假基因在世界各地的分布，我从来自18个不同种族的68人中，对编码TRPV1的6个跨膜区的约5kb的外显子9到11进行了测序。然而，在我们的样本中没有假基因的例子。其他群体遗传学分析正在进行中，结果将在2007.3年内提交给一份国际期刊)除了上述结果外，还发表了一篇关于感觉受体在人类进化中的作用的综述(日文)。

Animals sense ambient physico-chemical fluctuations through receptors in their sensory systems. The temperature sensors are capable of detecting and discriminating stimuli over a broad spectrum of temperatures. These sensors are members of three subfamilies (TRP V, TRPM and TRPA) of the transient receptor potential (TRP) family. In this project, there are two aims : 1) To infer the molecular evolution of these temperature receptors and 2) to clarify the origin of the diversity among human thermo-sensory receptors.1)Molecular evolution of temperature receptors in vertebrates : A larger number of TRP paralogs have been found in terrestrial animal genomes than in the fish genome, reflecting different extent of temperature fluctuations in environments. In mammals, there are nine thermo-sensory receptor genes, of which four (TRPV1'4) are responsible for sensing either warm or hot. Phylogenetic studies of TRPV1-.4 genes in vertebrates have revealed excessive amino acid substitutions in the stem lineage of birds and mammals for each TRPV, suggesting either accelerated substitution rates or frequent occurrences of convergent evolution. These substitutions may be related to the development of body temperature controlling system in warm-blooded animals.2)The origin of the diversity among human thermo-sensory receptors : In NCBI record, there is a record of TRPV1 pseudogene. To examine the distribution of this pseudogene over the world, I sequenced approximately 5kb region encompassing exon9 to 11 encoding the 6 trans-membrane region of TRPV1 from 68 individuals from 18 different ethnic groups. However, there is no example o pseudogene in our sample. Other population genetics analyses are progressing and the result will be submitted to an international journal within 2007.3)In addition to the above results, a review (in Japanese) about a role of sensory receptors in the human evolution has been published.