Conclusions and future studies
This study showed that maternal effects manifested as gene expression
differences in interspecific hybrids of the coral A.tenuis and A. loripes . We also showed that maternal
effects can persist to at least seven months of age in coral and were
likely responsible for the phenotypes of F1 hybrids. However, exposure
to elevated temperature and p CO2 conditions did
not result in differential coral gene expression. Although the
composition of bacterial and microalgal endosymbiont communities of
these corals was similar under ambient and elevated conditions and
between hybrids and purebreds (Chan et al., 2019), these microbes may
have expressed different genes and contributed to holobiont phenotypic
differences. Other less studied members of the coral holobiont, such as
viruses and fungi (that were not examined), may also have contributed to
coral survival and size differences. Further, post-transcriptional and
epigenetic regulation (e.g., DNA methylation) may have varied between
treatments and hybrid and purebreds and may have resulted in phenotypic
differences (Dimond et al., 2017). Future studies will benefit from
adopting a multi-omics approach and assessing other members of the
coral-associated microbiome to explore other mechanisms that underpin
the phenotype of the coral holobiont.