Aug 26, 2018 at 5:00 AM
How do new species of plants and animals form?
That question has fascinated biologists ever since it was posed by Aristotle, the parent of biology.
Some species appear to increase dramatically over relatively short time periods. For example, more than 500 species of cichlid fish live in Africa’s Lake Victoria and nowhere else. Molecular genetic analyses presented at a recent symposium on such “adaptive radiations” of species suggest those fish species formed within just 15,000 years after the lake filled.
The American Genetic Association organized the symposium last month in Hawaii. The organization chose a good venue. Numerous species radiations have occurred on Hawaii, resulting in 28 species of silverswords, a group of plants related to sunflowers; 55 species of honeycreepers, a group of songbirds; and more than 800 species of fruit flies. Elizabeth Pennisi reported on the symposium this month in the journal Science.
You might recall the excitement surrounding the release of the first complete human genome in the early 2000s. Sequencing the entire genetic code of one human took more than a decade and cost millions of dollars.
Compare that with the 400 whole genomes from 150 different species of Lake Victoria cichlids presented at the symposium by Ole Seehausen from the University of Bern, Switzerland.
Seehausen and colleagues suggest that closely related cichlid species living in rivers near where Lake Victoria would form mated with one another. These hybrid matings generated increased genetic variance in cichlids, which then colonized the lake as it formed. Natural selection could then rapidly shape traits associated with newly forming nesting sites and mating behaviors associated with them, food sources, and feeding locales in the lake.
Receive News & Ratings Via Email - Enter your email address below to receive a concise daily summary of the latest news and analysts' ratings with MarketBeat.com's FREE daily email newsletter.
Several other symposium participants presented molecular genetic data suggesting that mating between closely related species could drive rapid species radiations. Examples included radiations of Central American tropical butterflies, microscopic crustaceans in Russia’s Lake Baikal, and 140 species of lobelioids, another group of closely related plants found only in Hawaii.
Quoted in Pennisi’s Science report, Seehausen suggests that “hybridization may turn out to be the most powerful engine of new species and new adaptations.”
Several species in Ohio and environs also display unusually high diversity, which might suggest hybridization followed by new species formation occurred among their ancestors.
The highest diversity of salamander species in the world occurs in the Appalachian Mountains, including parts of southeastern Ohio. Similarly, rivers and streams in Ohio, Indiana and Illinois support some of the highest diversities of freshwater mussels found anywhere in the world.
Compare the 38 species of freshwater mussels found in the Darby Creek watershed southwest of Columbus with the 10 species of the group found in Europe and the 38 species found in all of China.
Habitat destruction threatens the biodiversity of local and regional salamander and mussel species. An epidemic caused by an invasive fungus species also threatens many of the same salamanders and their amphibian relatives.
Ironically, just as we have acquired the molecular genetic tools to understand better how the biodiversity of life around us formed, we also are losing much of that diversity forever because of habitat destruction and climate change.
Steve Rissing is a biology professor at Ohio State University.
Just-released report names Cannabis Stock of the Year for 2019! Their last pick has seen a +1,200% return since he released it!
This stock has all of the makings of the next great cannabis stock – early-mover advantage, international exposure and influential partnerships, plus it has a product that is unlike anything else on the market…