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Complex evolution of orthologous and paralogous decarboxylase genes
Author(s) -
SáenzdeMiera L. E.,
Ayala F. J.
Publication year - 2004
Publication title -
journal of evolutionary biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.289
H-Index - 128
eISSN - 1420-9101
pISSN - 1010-061X
DOI - 10.1046/j.1420-9101.2003.00652.x
Subject(s) - biology , gene , genetics , evolutionary biology , molecular evolution , computational biology , genome
The decarboxylases are involved in neurotransmitter synthesis in animals, and in pathways of secondary metabolism in plants. Different decarboxylase proteins are characterized for their different substrate specificities, but are encoded by homologous genes. We study, within a maximum‐likelihood framework, the evolutionary relationships among dopa decarboxylase ( Ddc ), histidine decarboxylase ( Hdc ) and α‐methyldopa hypersensitive ( amd ) in animals, and tryptophan decarboxylase ( Wdc ) and tyrosine decarboxylase ( Ydc ) in plants. The evolutionary rates are heterogeneous. There are differences between paralogous genes in the same lineages: 4.13 × 10 −10 nucleotide substitutions per site per year in mammalian Ddc vs. 1.95 in Hdc ; between orthologous genes in different lineages, 7.62 in dipteran Ddc vs. 4.13 in mammalian Ddc ; and very large temporal variations in some lineages, from 3.7 up to 54.9 in the Drosophila Ddc lineage. Our results are inconsistent with the molecular clock hypothesis.