A reassessment of mammalian alpha A-crystallin sequences using DNA sequencing: Implications for anthropoid affinities of tarsier

被引:19
作者
Jaworski, CJ
机构
[1] Section on Molecular Structure and Function, Laboratory of Molecular and Developmental Biology, National Eye Institute, National Institutes of Health, Bethesda, Maryland, 28092, Room 222
关键词
alpha A-crystallin; Tarser; DNA sequencing; anthropoid;
D O I
10.1007/BF00173170
中图分类号
Q5 [生物化学]; Q7 [分子生物学];
学科分类号
071010 ; 081704 ;
摘要
alpha A-crystallin, a major structural protein in the ocular lenses of all vertebrates, has been a valuable tool for molecular phylogenetic studies. This paper presents the complete sequence for human alpha A-crystallin derived from cDNA and genomic clones. The deduced amino acid sequence differs at two phylogenetically informative positions from that previously inferred from peptide composition. This led us to examine the same region of the alpha A-crystallin gene in 12 other mammalian species using direct sequencing of PCR-amplified genomic DNA. New sequences were added to the database, and corrections were made to all anthropoid sequences, defining clear synapomorphies for anthropoids as a clade distinct from prosimians. Within the anthropoids there are further synapomorphies delineating hominoids, Old World monkeys, and New World monkeys. Significantly, sequence revisions and the addition of new sequence for a prosimian, the sifaka, eliminate the previous support for the proposed anthropoid affinities of the tarsier inferred from alpha A-crystallin protein sequences. In addition, DNA sequences provide greater resolution of certain relationships. For example, although they are identical in protein sequence, comparison of DNA sequences clearly separates mouse and the common tree shrew, grouping the tree shrew closer to prosimians. These results show that adding DNA sequences to the to the existing alpha A-crystallin database can enhance its value in resolving phylogenetic relationships.
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页码:901 / 908
页数:8
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