1998/12/07 by Nancy Knowlton, Lee A. Weigt · 3 citations
Biochemistry, Genetics and Molecular Biology · Environmental Science · #Genetic diversity and population structure #Coral and Marine Ecosystems Studies #Genomics and Phylogenetic Studies #Panama #Divergence (linguistics) #Gene flow #Biology #Genetic divergence #Genus #Sister group #Taxon #Evolutionary biology #Ecology #Zoology #Clade #Genetic variation #Genetic diversity #Phylogenetics #Gene #Genetics #Demography
paper · doi:10.1098/rspb.1998.0568
openalex publication_date 1998/12/07 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/01
Sister species separated by the Isthmus of Panama have been widely used to estimate rates of molecular evolution. These estimates are based on the assumption that geographic isolation occurred nearly simulta-neously for most taxa, when connections between the Caribbean and eastern Paci¢c closed approximately three million years ago. Here we show that this assumption is invalid for the only genus for which many taxa and multiple genetic markers have been analysed. Patterns of divergence exhibited by allozymes and the mitochondrial COI gene are highly concordant for 15 pairs of snapping shrimp in the genus Alpheus, indicating that they provide a reasonable basis for estimating time since cessation of gene £ow. The extent of genetic divergence between pairs of sister species varied over fourfold. Sister species from mangrove environments showed the least divergence, as would be expected if these were among the last habitats to be divided. Using this pair yields a rate of sequence divergence of 1.4 % per one million years, with implied times of separation for the 15 pairs of 318 million years ago. Many past studies may have overestimated rates of molecular evolution because they sampled pairs that were sepa-rated well before ¢nal closure of the Isthmus.