Purifying selection in Grouse is more efficient in large populations

• Inbreeding depression and purging are recognized as essential factors to be considered in conservation programs. Elevated levels of both can increase the risk of population extinction by negatively impacting fitness-related characters in many species of plants and animals, including humans. Genomic techniques are increasingly used in measuring and understanding inbreeding and inbreeding depression and their importance in evolution and conservation. We use whole genome resequencing data from isolated, bottlenecked, and outbred Tetrastes and Lagopus populations in subarctic Eurasia to quantify inbreeding depression and purifying selection. We found a large range of inbreeding measured as FROH in populations of Chinese Grouse (Tetrastes sewerzowi) and Hazel Grouse (T. bonasia). FROH estimated from genome-wide runs of homozygosity (ROH) ranged from 0.02 to 0.24 among Chinese Grouse populations and 0.01 to 0.44 in Hazel grouse. A population of Chinese Grouse residing in the Qilian mountains and the European populations of Hazel Grouse (including samples from Sweden, Germany and North East Poland) were both highly inbred (FROH ranged from 0.10 to 0.23 and 0.11 to 0.44, respectively). Hazel grouse from northern China and Chinese grouse residing in the Qinghai-Tibetan Plateau showed relatively lower inbreeding levels. In addition, through comparison of the ratio between deleterious missense mutations and synonymous mutations, purifying selection was found to be more efficient in Hazel grouse and ptarmigan populations which hold larger population sizes than Chinese grouse. However, when we compared the ratio between loss-of-function and synonymous mutations, Hazel Grouse had slightly higher levels than Chinese Grouse while Willow Ptarmigan and Rock Ptarmigan had lower levels of genetic load. These results indicate that purifying selection has been more efficient in the wide ranging hazel grouse which thereby can sustain higher levels of inbreeding compared to Chinese grouse. Our study provides the first genetic evidence of inbreeding depression and purging patterns in boreal forest species in Eurasia from the respective sibling species and provide relevant information for future conservation and management of the species.

Ämnesord

NATURVETENSKAP  -- Biologi -- Evolutionsbiologi (hsv//swe)

NATURAL SCIENCES  -- Biological Sciences -- Evolutionary Biology (hsv//eng)

NATURVETENSKAP  -- Biologi -- Genetik (hsv//swe)

NATURAL SCIENCES  -- Biological Sciences -- Genetics (hsv//eng)

Publikations- och innehållstyp

vet (ämneskategori)

ovr (ämneskategori)