Researchers from Duke University have discovered that nematode worms cope with starvation better if their mothers had also been malnourished. The young worms were not as likely to become stunted when underfed, as long as their mothers hadn’t gotten enough food during pregnancy. The findings are in a paper that was just published in the journal PLOS Genetics.
A nematode worm called the roundworm (Caenorhabditis elegans) is used as a model in biology research due to the simplicity of their nervous system and genes. They are also transparent, making it easy to study cellular activity without killing the worm.
The research team took pregnant roundworms and gave some of the animals a nutritious broth diet while the others were given a less nutritious version. The starved worms gave birth to fewer, but larger, offspring when compared to the control group. These larger offspring were much more resistant to starvation and their growth was not as stunted when they were fed a non-nutritious diet. They were also quicker to recover from starvation and thrived once given access to food again. There was one downside for the offspring of starved mothers—they were less fertile. This could be reversed with a healthy diet later in life, however.
The team speculates that malnourishment during pregnancy may prompt the body to focus on developing fewer, but stronger, eggs. Starvation may slow down the ovulation process, allowing the egg to become more developed before fertilization. Another theory, backed up by existing research, is that starvation during pregnancy causes genetic changes that can be inherited by the babies. A change in gene expression may better prepare offspring for difficult environmental conditions.
Starved roundworm mothers are able to prepare their young for poor food availability but the exact mechanisms behind this phenomenon are unknown. Offspring from starved mothers were quicker to bounce back from famine conditions. The researchers believe that these findings show a link between maternal diet and gene expression, a connection that may affect other animal species, including humans.
Hibshman JD, Hung A, Baugh RL. Maternal Diet and Insulin-Like Signaling Control Intergenerational Plasticity of Progeny Size and Starvation Resistance. PLOS Genetics (2016).