Due to limited geographic ranges, island populations, in general, are expected to have smaller population sizes and a limited influx of migrants compared to populations inhabiting continental mainlands. Therefore, island populations are expected to be influenced by genetic drift and natural selection differently from mainland populations. In this study, I aimed at investigating potential island effects in cryptic wood white (Leptidea juvernica), and the main hypothesis of this study was that island populations will show less efficient purifying selection than mainland populations. I used whole-genome re-sequencing data from three cryptic wood white butterfly populations sampled in Ireland, Kazakhstan and Sweden and applied population genomics to assess levels of genetic diversity and quantify potential variation in the efficiency of natural selection by estimating site frequency spectra, assessing population structure, and applying various types of neutrality tests. The results show that the L. juvernica population in Ireland has comparatively low nucleotide diversity and increased genetic differentiation as compared to the mainland populations. Multiple types of neutrality / selection analyses revealed that purifying selection in Ireland has been less efficient than on the mainland. These findings contribute in several ways to the understanding of how selections act in island populations and provide insights into how evolutionary genetics / genomics can be informative for conservation efforts in isolated and declining island populations and other populations with limited distribution ranges.
| Identifer | oai:union.ndltd.org:UPSALLA1/oai:DiVA.org:uu-477752 |
| Date | January 2022 |
| Creators | Hu, Xuejing |
| Publisher | Uppsala universitet, Institutionen för biologisk grundutbildning, Uppsala University |
| Source Sets | DiVA Archive at Upsalla University |
| Language | English |
| Detected Language | English |
| Type | Student thesis, info:eu-repo/semantics/bachelorThesis, text |
| Format | application/pdf |
| Rights | info:eu-repo/semantics/openAccess |
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