Does Large Genome Size Limit Speciation in Endemic Island Floras?

Abstract EN

Genome sizes in plants vary by several orders of magnitude, and this diversity may have evolutionary consequences.

Large genomes contain mainly noncoding DNA that may impose high energy and metabolic costs for their bearers.

Here we test the large genome constraint hypothesis, which assumes that plant lineages with large genomes are diversifying more slowly Knight et al.

(2005), using endemic floras of the oceanic archipelagos of the Canaries, Hawaii, and Marquesas Islands.

In line with this hypothesis, the number of endemic species per genus is negatively correlated with genus-average genome size for island radiations on Hawaiian and Marquesas archipelagos.

However, we do not find this correlation on the Canaries, which are close to the continent and therefore have higher immigration rate and lower endemism compared to Hawaii.

Further work on a larger number of floras is required to test the generality of the large genome constraint hypothesis.