Balanced lethal systems: a quick guide by Ben Wielstra

Ben Wielstra studies balanced lethal systems, in which half of the offspring die before birth. In the journal Current Biology, he explains in an accessible way how such a disadvantage can originate in nature.

Northern banded newt (Ommatotriton ophryticus). Image by Michael Fahrbach.

In a balanced lethal system, two forms of a particular chromosome are necessary for viability. Yet, the parents both randomly pass one of the two forms to the next generation. Only half of the offspring have the correct chromosome combination and live; the other half die before birth. Ben Wielstra of the Institute of Biology Leiden and Naturalis Biodiversity Center studies this phenomenon in newts. He thinks the system is an ‘evolutionary trap’, which is beneficial in the short term, but detrimental in the long run. He wrote a clear explanation about this evolutionary mystery for the scientific journal Current Biology.

Until 25 August 2020, the article is available free of charge via this link.

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