Hybridization helps species avoid extinction

RIVERSIDE, Calif., Aug. 8 (UPI) -- Some species are more likely to resemble their parents than others. It depends on how genes are passed from generation to generation.

Humans get two copies of each of their 23 chromosomes, one from each parent. Humans are diploids. Polyploids, on the other hand, have several copies of their chromosomes, encouraging hybridization.

Unlike some hybrids, polyploid hybrids are fertile -- capable of producing offspring.

A new study, published in the journal Nature Plants, reveals an evolutionary advantage of hybridization among polyploid plant hybrids in the genus Nicotiana, often referred to as tobacco plants.

Nicotiana polyploid hybrids featured shorter, wider flowers to encourage pollination by a greater variety of species.

The approach of polyploid hybrids, which privileges generalization over specialization, is aided by the plants' ability to differentiate themselves from their parents.

The latest findings reveal nature's response to the problem of overspecialization, whereby flowers become too reliant on a specific pollinator or vice versa, and risk considerable losses should their evolutionary partner fade away.

"Some plants evolve increasingly specialized relationships with the species that pollinate them," lead researcher Elizabeth McCarthy, a post-doctoral researcher at the University of Riverside, said in a press release.

"Classic example is Darwin's Madagascan orchid, first discovered in 1798. Its exceptionally long nectar spur led Charles Darwin to propose that it was pollinated by a moth whose proboscis -- the organ that extracts the nectar -- was longer than that of any moth known at the time," McCarthy added. "Darwin's prediction was spectacularly verified 21 years after his death when just such a moth was discovered."