5 Conclusion
Our study represents a unique case of diploid and triploid individuals from the same species invading an extreme high-altitude environment. The results demonstrated profoundly different outcomes of the invasion process at the genomic level for diploids and triploids. For diploids, in spite of introductions from two genetically distinct sources, the invasive individuals possessed significantly lower heterozygosity than source individuals and formed a genetic cluster distinct from the source populations. Demographic history reconstruction also documented recent population declines coinciding with invasion. Nevertheless, inbreeding was still low, presumably reflecting buffering effects of multiple continuous events of introduction. For triploids, no change in genetic diversity and structure was found in invasive populations, which is owing to their reproduction mode of gynogenesis that precludes inbreeding and reduces founder effects. Finally, there evidence for selective sweeps in invasive diploid goldfish, pointing to a role of mannosidase activity that nevertheless requires further clarification and embryo development, the latter of which may play important roles for adaptive processes of individuals introduced into this extreme environment.