ISSN:
1432-1432
Keywords:
Genomic cloning
;
DNA sequencing
;
Multigene family
;
S1 mapping
;
Promoter region
;
Gene expression
;
Concerted evolution
;
Repetitive DNA
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
Notes:
Abstract Cow stomach lysozyme genes have evolved in a mosaic pattern. The majority of the intronic and flanking sequences show an amount of sequence difference consistent with divergent evolution since duplication of the genes 40–50 million years ago. In contrast, exons 1, 2, and 4 and immediately adjacent intronic sequences differ little between genes and show evidence of recent concerted evolution. Exon 3 appears to be evolving divergently. The three characterized genes vary from 5.6 to 7.9 kilobases in length. Different distributions of repetitive DNA are found in each gene, which accounts for the majority of length differences between genes. The different distributions of repetitive DNA in each gene suggest the repetitive elements were inserted into each gene after the duplications that give rise to these three genes and provide additional support for divergent evolution for the majority of each gene. The observation that intronic and flanking sequences are evolving divergently suggests that the concerted evolution events involved in homogenizing the coding regions of lysozyme genes involve only one exon at a time. This model of concerted evolution would allow the shuffling of exon-sized pieces of information between genes, a phenomenon that may have aided in the early adaptive evolution of stomach lysozyme.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00178866
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