Why Are Genetically Identical Individuals Different? Ask Your Mom!


Summary: Researchers reveal maternal age has an impact on variations between genetically identical individuals.

Source: Center For Genomic Regulation.

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 identical C. elegans worms. Their results have been published in Nature.

“Our lab has long been interested in understanding why genetically identical individuals sharing the same environment still often differ substantially in their characteristics,” explains Ben Lehner, ICREA Professor and Coordinator of the Systems Biology Program at CRG. “Through a rather circuitous route, we have now identified a major cause of these differences in one of the main model organisms that we study.”

“We observed that the age of a mother has a major impact on the physiology of her offspring” states Marcos Francisco Perez, PhD student and co-first author of this work. “Surprisingly we found that it is the youngest mothers that produce offspring that are impaired for many characteristics such as their size, growth rate, and starvation resistance” explains post-doctoral researcher and co-first author of the study, Mirko Francesconi. “The offspring of young mothers also have fewer offspring themselves when they become adults,” he adds.

“These differences are caused in part because young mothers provide less of a specific protein complex to their embryos,” adds Marcos Francisco Perez. Why would a worm produce low quality progeny early in life? “Producing progeny early in life, even if they are lower quality, has a major benefit because it dramatically shortens the generation time of the species,” explains Marcos Francisco Perez.

Caenorhabditis elegans embryo showing yolk and intestinal fluorescence. NeuroscienceNews.com image is credited to Lola Davey, Marcos Francisco Perez, CRG.

“What’s particularly interesting is that the age of an individual’s mother determines their characteristics throughout their lives,” adds Ben Lehner. “This is a really interesting example of how the physiology of a previous generation can alter not only the development of an animal but also its characteristics as a mature adult.”

Of worms and humans

Ben Lehner and his team are interested in understanding what makes individuals different and how these differences originate in the interactions between genetic, environmental, ancestral and stochastic sources of variation. Worms are a great species to use in this type of study, because scientists can raise large populations of genetically identical individuals in the same laboratory environment. Worms and humans are evolutionarily distant but still share a large fraction of their genes, as well as most of the major genetic pathways which regulate development, metabolism and nutrition. Still, their results concerning the effect of maternal age do not translate to humans but illustrate the kind of ways in which differences between genetically identical individuals might arise.

“Our results are also important for the thousands of people doing research in this species. People don’t consider maternal age when designing experiments but now we have shown that it is an important factor,” conclude the scientists.

About this neuroscience research article

Funding: Funding provided by European Research Council Consolidator Grant, Spanish Ministry of Economy and Competitiveness, AXA Research Fund, Bettencourt Schueller Foundation, and others.

Source:Center For Genomic Regulation
Publisher: Organized by NeuroscienceNews.com.
Image Source: NeuroscienceNews.com image is credited to Lola Davey, Marcos Francisco Perez, CRG.
Original Research: Abstract for “Maternal age generates phenotypic variation in Caenorhabditis elegans” by Marcos Francisco Perez, Mirko Francesconi, Cristina Hidalgo-Carcedo & Ben Lehner in Nature. Published online November 29 2017 doi:10.1038/nature25012

Cite This NeuroscienceNews.com Article

Center For Genomic Regulation “Why Are Genetically Identical Individuals Different? Ask Your Mom!.” NeuroscienceNews. NeuroscienceNews, 30 November 2017.
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Center For Genomic Regulation (2017, November 30). Why Are Genetically Identical Individuals Different? Ask Your Mom!. NeuroscienceNews. Retrieved November 30, 2017 from http://neurosciencenews.com/genetic-differences-twins-8072/

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Abstract

Maternal age generates phenotypic variation in Caenorhabditis elegans

Genetically identical individuals that grow in the same environment often show substantial phenotypic variation within populations of organisms as diverse as bacteria, nematodes, rodents and humans. With some exceptions the causes are poorly understood. Here we show that isogenic Caenorhabditis elegans nematodes vary in their size at hatching, speed of development, growth rate, starvation resistance, fecundity, and also in the rate of development of their germline relative to that of somatic tissues. We show that the primary cause of this variation is the age of an individual’s mother, with the progeny of young mothers exhibiting several phenotypic impairments. We identify age-dependent changes in the maternal provisioning of the lipoprotein complex vitellogenin to embryos as the molecular mechanism that underlies the variation in multiple traits throughout the life of an animal. The production of sub-optimal progeny by young mothers may reflect a trade-off between the competing fitness traits of a short generation time and the survival and fecundity of the progeny.

“Maternal age generates phenotypic variation in Caenorhabditis elegans” by Marcos Francisco Perez, Mirko Francesconi, Cristina Hidalgo-Carcedo & Ben Lehner in Nature. Published online November 29 2017 doi:10.1038/nature25012

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