How to build a new species by inverting its genomeS

The yellow monkeyflower is in the process of splitting into two separate species. But how does this happen? Now scientists understand better how to make one species into two.

The yellow monkeyflower splits into two new species in two stages. First, it needs to find two different sets of conditions that it can adapt to. Secondly, it needs to keep the plants that adapt to these conditions separate, in order to keep them from interbreeding.

It does the first by adapting to two different terrains. The coastal monkeyflower is meant to live in moist, salty areas with a lot of dense greenery. The inland flower is adapted to live in dry, open places. The plants don't mix their genes because the inland plant flowers early in the spring, when there's water, and the coastal plant takes its sweet time.

The question is, how does the one plant do two separate things? David Lowry found out that the plant managed to take a section of one chromosome and turn it upside down. The result was a new suite of genes.

A release on the paper, published in PLoS Biology, explains:

A single species with a broad range of habitats like the monkeyflower can be expected to have a suite of genes available to help it adapt to the various conditions it would encounter within its range. But depending on where an individual plant finds itself, some of those genes aren't being used. . . . The inversion can be a driver of speciation. In the process of gene-shuffling during the formation of sex cells (known as recombination), an inverted region can't successfully swap genes with its counterpart chromosome precisely because it's backwards.

A better understanding of inversions isn't just a help to botanists. Several genome inversions have been found between humans and chimpanzees. Maybe the original separation between us and them started when something turned a sequence of their genome on its head.

Via the PLoS Biology.