Allelic variation of Mhc class II in Atlantic salmon; a population genetic analysis
Author
Summary, in English
We have studied the degree of genetic variation at a variable Mhc class II beta gene in four populations of Atlantic salmon Salmo salar by using RFLPs. The class II beta gene encodes the part of the Mhc class II molecule that contains the antigen binding region and is therefore essential for disease resistance. There was extensive genetic variation in all four populations; the expected heterozygosity (H-si) varied between 0.50 and 0.81. Heterozygosity tended to be higher in broods surviving a syndrome causing high mortalities (60-95%) in Swedish salmon hatcheries. Populations that had experienced more incidences of genetic bottlenecks (years when fewer than 60 adults had been used for breeding) and had a lower average effective population size (N-e), had a lower degree of heterozygosity. The four populations differed significantly in allele frequencies as measured by F-ST = 0.13 and Nei's genetic distance (D = 0.09 - infinity). Pairwise F-ST values varied between 0.01 and 0.23, all but one being highly significant, indicating a differentiation between the populations in Mhc class II beta. This study shows that the four populations of Atlantic salmon have a high degree of polymorphism in the Mhc class II beta gene. However, there was great variation between different hatcheries, both in heterozygosity levels and allele frequencies.
Publishing year
1998
Language
English
Pages
568-575
Publication/Series
Heredity
Volume
80
Issue
5
Links
Document type
Journal article
Publisher
Macmillan
Topic
- Biological Sciences
- Ecology
Keywords
- allele frequency
- Atlantic salmon
- genetic variation
- heterozygosity
- Mhc
- population
- major histocompatibility complex
- electrophoretic variation
- f-statistics
- diversity
- trout
- polymorphism
- variability
- selection
- pacific
- salar
Status
Published
Research group
- Molecular Ecology and Evolution Lab
ISBN/ISSN/Other
- ISSN: 1365-2540