Biologists find new genetic interdependence between mothers and their offspring

October 2, 2018, New York University
Credit: CC0 Public Domain

A team of biologists has discovered that the distinctive genetic processes of early development help explain patterns of animal development in nature and across the evolutionary tree. Its findings point to a largely overlooked dynamic between the genome of mothers and their developing progeny—and one that underscores this genetic interaction as a primary influence on evolution.

"Some traits, such as size, are determined by the mother's genome, but other offspring traits are shaped by the offspring's genome itself," explains Matthew Rockman, an associate professor in New York University's Department of Biology and the senior author of the paper, which appears in the journal eLife. "As a result, there may be genetic mismatches between mother and offspring, which can sometimes hinder adaptation to ecological conditions."

The study, the first genetic analysis of a transition from indirect to direct development, one of the most common evolutionary patterns across the history of animal life, was led by Christina Zakas, an NYU postdoctoral research scientist.

Many animals develop indirectly, growing first into a larva that must feed itself before metamorphosis into its juvenile form. However, some lineages have abandoned this larval mode of development, switching to direct development—skipping the larval phase and hatching as a small version of the adult.

Direct and indirect developing lineages therefore have very different offspring, with large differences in size and morphology between them. But how this kind of evolutionary transition happens, at the genetic level, has long been a mystery to scientists.

In their study, the NYU researchers examined a small marine worm, Streblospio benedicti, which is found in New York harbor. The species serves as a good vehicle for examining the larva-to-direct-development change because some populations of this species make larvae while others develop directly.

Using genetic crosses in the lab to isolate differences in the worms' offspring, the scientists sought to discover the genomic regions responsible for . By tracking pieces of genome along the family tree of their experimental worms, they could distinguish among alternative genetic models.

Surprisingly, their results showed that the genes that govern egg size are completely independent of the genes that influence larval development.

"This genetic independence means that matings between populations that differ in developmental mode will generate genetically mismatched offspring," Rockman notes. "Moreover, because egg size is determined by the mother's genes and larval development by the offspring genotype, the special circumstances of early development create a feedback loop: the frequency of the maternal genes in a population creates its own selection pressure for matching offspring ."

The findings, then, suggest a previously unexplored mechanism shaping in this and other species.

"Different ecological circumstances favor one approach or the other, but our results show that in this species the effects of the maternal could override other selective pressures from the environment such as salinity, predators, or food abundance," says Rockman.

Explore further: Age of mothers influences genetic similarity between twins

More information: Christina Zakas et al, Decoupled maternal and zygotic genetic effects shape the evolution of development, eLife (2018). DOI: 10.7554/eLife.37143

Related Stories

Age of mothers influences genetic similarity between twins

November 30, 2017

Does the age of a mother influence the traits and characteristics of her progeny, and how? A team of scientists at the Centre for Genomic Regulation (CRG) in Barcelona have addressed these questions by studying tiny, genetically ...

Why a 'cuckoo in the nest' can go undetected

September 27, 2018

Researchers at the Universities of Exeter and Cambridge have shed light on why some species cannot tell the difference between their own offspring and those of intruders that have been slipped into their nests.

Frogs reveal mechanism that determines viability of hybrids

January 11, 2018

Why are some hybrids viable and others not? It is known that this depends on the father species and the mother species. New research in two related frog species shows the influence of mother and father species: One hybrid ...

Generous mothers are nagged less

January 6, 2016

If a mother is already a generous provider, her offspring will nag her less, according to new research in mice by University of Manchester scientists.

Recommended for you


Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.