Molecular Evolution of Pituitary Hormones

IBN-9507171 Dores，Robert M. 以前试图通过比较低分子量多肽激素家族的序列来评估脊椎动物的生殖，一般来说，不能令人满意的生殖树。 这是由于小的尺寸和高度的保守性，使得肽结构中没有足够的差异来构建适当的树。 此外，基于这些数据构建的树在建立一个物种与另一个物种的关系时会导致错误。 然而，Robert Dores博士认为，通过研究垂体激素前体分子的结构可以获得与遗传学相关的信息，因为它们的尺寸比激素本身大。 在目前的研究中，Dores博士建议从许多不同物种的脑垂体中分离和测序编码阿黑皮素原的基因。 通过比较这些基因的序列，使用最大简约法程序，一个准确的系统发育图，这些物种与其他脊椎动物的发展将是可能的。 阿黑皮素原是促肾上腺皮质激素、黑皮质素和β-内啡肽的前体分子，是一种有效的内源性镇痛分子，这一新信息将为几个物种之间的关系提供更直接的证据。 此外，通过对编码阿黑皮素原（重要的哺乳动物应激分子促肾上腺皮质激素的前体）的基因进行测序，可以获得关于人类应激反应的新信息。

IBN-9507171 Dores, Robert M. Previous attempts at evaluating phylogeny of vertebrates by comparing sequences of low molecular weight polypeptide hormone families have yielded, in general, unsatisfactory phylogentic trees. This is due to the small size and high degree of conservation, such that there are not adequate differences in peptide structure to construct appropriate trees. Moreover, construction of trees based on these data have lead to errors in establishing the relationship of one species to another. However, Dr. Robert Dores believes that phylogenetically relevant information may be obtained by investigating the structure of the precursor molecules for the pituitary hormones, due to their larger size as opposed to the hormones themselves. In the present studies, Dr. Dores proposes to isolate and sequence the gene encoding proopiomelanocortin from the pituitary of a number of different species. By comparing the sequences of these genes using maximum parsimony procedures, development of an accurate phylogenetic map relating these species with other vertebrates will be possible. This new information about proopiomelanocortin, the precursor molecule for corticotropin, melanocortin and beta-endorphin, a potent endogenous analgesic molecule, will provide more direct evidence for the relationship between several species. In addition, by sequencing the gene encoding proopiomelanocortin, the precursor for the important mammalian stress molecule, corticotropin, new information about stress responses in humans may be obtained.