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.