Mitochondrial cytochrome b gene sequences were obtained from representatives of five populations of the Cape galaxias Galaxias zebratus. Four highly distinct genotypes were revealed, with sequence divergence values ranging from 5.8 to 13.8%. Some of the pairwise divergences are the highest yet reported for cytochrome b within a fish species, and are more typical of interspecific and intergeneric comparisons. In contrast, the low genetic divergence (0.3%) between two recently recorded populations from the Krom and Gamtoos (Kouga) Rivers indicates recent gene flow. Parsimony analysis consistently produced a tree with the population from the Olifants River on the west coast as ancestral and eastern populations as progressively more derived. Estimated divergence times for the Olifants population range from 4.4 to 6.6 million years ago. The findings suggest that another detailed revision is required to determine whether these divergent populations represent a single species or a species complex.

Item Type:	Refereed Article
Research Division:	Biological Sciences
Research Group:	Zoology
Research Field:	Zoology not elsewhere classified
Objective Division:	Expanding Knowledge
Objective Group:	Expanding Knowledge
Objective Field:	Expanding Knowledge in the Environmental Sciences
Author:	Waters, JM (Associate Professor Jon Waters)
ID Code:	11116
Year Published:	1997
Web of Science® Times Cited:	33
Deposited By:	Zoology
Deposited On:	1997-08-01
Last Modified:	2011-08-11
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