A research team led by scientists at Penn State has made a discovery that contests the long-held belief that changes in DNA sequences which occur in non-reproductive cells cannot be passed to offspring. For the first time, the researchers have determined that corals can pass mutations acquired during their lifetimes to their offspring,
“For a trait, such as growth rate, to evolve, the genetic basis of that trait must be passed from generation to generation. For most animals, a new genetic mutation can only contribute to evolutionary change if it occurs in a germline or reproductive cell, for example in an egg or sperm cell. Mutations that occur in the rest of the body, in the somatic cells, were thought to be evolutionarily irrelevant because they do not get passed on to offspring. However, corals appear to have a way around this barrier that seems to allow them to break this evolutionary rule,” explained Professor Iliana Baums, who led the research.
Study co-author Kate Vasquez Kuntz explained how this might be possible: “In most animals, reproductive cells are segregated from body cells early in development. So only genetic mutations that occur in the reproductive cells have the potential to contribute to the evolution of the species. However, for some organisms, like corals, the segregation of reproductive cells from all other cells may occur later in development or may never occur at all, allowing a path for genetic mutations to travel from a parent’s body to its offspring.”
Because corals can reproduce asexually via budding and colony fragmentation, they were the ideal organisms for the study.
“This single-parent reproduction allowed us to more easily search for potential somatic mutations from the parent coral and track them into the offspring by simplifying the total number of genetic possibilities that could occur in the offspring.” said study co-author Sheila Kitchen.
The researchers hope that with the ability of parent corals to pass on potentially advantageous mutations, their offspring will have a better chance of survival.
“If these mutations can then be passed on to offspring – as we have now demonstrated – it means that corals have an additional tool that might be able to speed up their adaptation to climate change,” said Professor Baums.
The research is published in the journal Science Advances.