![]() ![]() The models that the team developed can be applied to a wide range of species to evaluate the fitness consequences of maternal effect senescence. They don't yet fully understand the genetic mechanisms that cause offspring quality to decrease with maternal age. "Because of this, maternal effect senescence will persist and continue to evolve in the population, even though it results in decreased fitness," Gribble adds. "Because the selection pressure decreases as the mothers age, it may not be strong enough to remove these less-fit from the population," Hernandez says. They found this pressure, called the selection gradient, declines with maternal age. To address this, Hernández and collaborators built mathematical models to calculate, for the first time, the strength of natural selection pressure on the survival and fertility of offspring populations as functions of the age of their mothers. So why do we see this phenomenon across so many species?" "Natural selection should weed out these less-fit offspring of older mothers. "This study is unique in that it combines laboratory data from our prior work with mathematical modeling to address a longstanding question in the evolution of aging," Gribble says. The study, led by Kristin Gribble of the Marine Biological Laboratory and Christina Hernández of Woods Hole Oceanographic Institution, is published this week in Proceedings of the National Academy of Sciences. They also suggest an evolutionary mechanism for why this may occur. They confirmed that this effect of older maternal age, called maternal effect senescence, does reduce evolutionary fitness of the offspring in all environments, primarily through reduced fertility during their peak reproductive period. Join the conversation at the SQPN Facebook page.In a new study in rotifers (microscopic invertebrates), scientists tested the evolutionary fitness of older-mother offspring in several real and simulated environments, including the relative luxury of laboratory culture, under threat of predation in the wild, or with reduced food supply.Purchase Star Trek books and Blu-ray/DVDs of Star Trek series and movies at the Secrets of Star Trek Store.Discovery and Picard are available at CBS All Access. ![]() You can watch most Star Trek series on Netflix or Amazon.Help us continue to offer the Secrets of Star Trek. Subscribe using the RSS feed | Subscribe using Apple Podcasts | Subscribe using Google Podcasts | Subscribe using Stitcher | Subscribe by Email. ![]() Get all new episodes automatically and for free: Cory Sticha examine the connections and delve into questions of artificial personhood, parents’ rights, and what Riker’s intentions really were toward Data’s daughter. SST107: TNG’s The Offspring is a significant foundation for the Picard series. ![]()
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