Epigenetic and behavioural variability in an isogenic lineage of Kryptolebias marmoratus during domestication under stable laboratory condition

Details

Supervisors

Silvestre, Frédéric

Faculty

Faculté des sciences

Degree label

Master [120] en biologie des organismes et écologie, à finalité approfondie

Abstract

Domestication begins with the transfer of individuals from their natural environment to a captive environment. These individuals, coming from a complex heterogeneous environment with fluctuating abiotic conditions, must adapt to a new environment with much more stable conditions and the presence of humans. In this context, phenotypic changes, such as behavioural variations, may appear from the first generation reared in captivity, raising the hypothesis that epigenetic mechanisms are involved in this process. We investigate this behavioural and epigenetic variability in the Emerson Point Preserve (EPP) population of the self-fertilising hermaphrodite fish Kryptolebias marmoratus, the mangrove rivulus, in wild individuals (F0) and in individuals reared under stable laboratory conditions for five generations (F5). This isogenic line offers the opportunity to work with individuals presenting low genetic diversity in order to study the involvement of epigenetic mechanisms in this species under captive conditions. An open field behavioural test to measure boldness, activity and thigmotaxis in fish was performed in duplicate, showing a decrease in boldness, activity, and anxiety, as well as individuality with captivity. DNA methylation at CpG sites was studied and showed significant differences in methylation between the two groups, with overall hypermethylation and low methylation variability in wild individuals compared to captive individuals. The stable conditions of captivity induce a loss of this methylation but with more variability within the group. The next step will be to identify the genes and their function that are influenced and regulated by these methylome variations.