Tropics found to harbor higher degree of intraspecific diversity than other parts of the world

September 30, 2016 by Bob Yirka, report

Tropical forest in Martinique near the city of Fond St-Denis. Credit: Wikipedia
(—A team of researchers with the University of Copenhagen's Natural History Museum of Denmark has found that the degree of intraspecific diversity is higher in the tropics than in other parts of the world. In their paper published in the journal Science, the team describes how they used information from public databases to gather information about diversity around the world and how they used it to map global diversity patterns. Henrique Pereira with the German Centre for Integrative Biodiversity Research offers a broader view on the work done by the team in a Perspectives piece in the same journal issue.

Prior research has shown that there is more plant and in the tropics than anywhere else on the planet. In this new effort, the researchers have found the same thing to be true regarding intraspecific (occurring within a species) diversity, at least as it applies to terrestrial mammals and amphibians. They also found that such diversity levels fall near human settlements.

To gain a better perspective regarding differences in intraspecific diversity across the world the researchers queried databases that hold information that publications require to be used before publication of papers regarding animal research. This gave them information regarding 318,000 mitochondrial DNA sequences for animals of the specific two taxa found all over the world. But they soon found that not all could be used for their study because they lacked adequate geographical data—after sifting they were left with 93,000 usable samples which covered approximately 4,700 species. They proceeded to create a virtual grid placed over the planet consisting of ~400-km cells and then assigned each of the samples to a cell.

Once that was complete, they created averages for each cell. Doing so allowed them to measure intraspecific diversity at a more specific level than has ever been done before. It also allowed them to see that intraspecific diversity levels followed closely with diversity levels in general, which meant that the tropics are the most diverse in both categories. It also allowed them to see the impact of human community building—the closer the cells were to such settlements, the lower the diversity levels in them fell.

No one really knows why the tropics are more diverse, but this new research offers support for the theory that suggests that hotter climates cause more genetic mutations in the creatures that live there.

Explore further: Brittle star study reveals richness and diversity of deep-sea life

More information: A. Miraldo et al. An Anthropocene map of genetic diversity, Science (2016). DOI: 10.1126/science.aaf4381

The Anthropocene is witnessing a loss of biodiversity, with well-documented declines in the diversity of ecosystems and species. For intraspecific genetic diversity, however, we lack even basic knowledge on its global distribution. We georeferenced 92,801 mitochondrial sequences for >4500 species of terrestrial mammals and amphibians, and found that genetic diversity is 27% higher in the tropics than in nontropical regions. Overall, habitats that are more affected by humans hold less genetic diversity than wilder regions, although results for mammals are sensitive to choice of genetic locus. Our study associates geographic coordinates with publicly available genetic sequences at a massive scale, yielding an opportunity to investigate both the drivers of this component of biodiversity and the genetic consequences of the anthropogenic modification of nature.

Related Stories

Recommended for you

A decade on, smartphone-like software finally heads to space

March 20, 2019

Once a traditional satellite is launched into space, its physical hardware and computer software stay mostly immutable for the rest of its existence as it orbits the Earth, even as the technology it serves on the ground continues ...

Tiny 'water bears' can teach us about survival

March 20, 2019

Earth's ultimate survivors can weather extreme heat, cold, radiation and even the vacuum of space. Now the U.S. military hopes these tiny critters called tardigrades can teach us about true toughness.

Researchers find hidden proteins in bacteria

March 20, 2019

Scientists at the University of Illinois at Chicago have developed a way to identify the beginning of every gene—known as a translation start site or a start codon—in bacterial cell DNA with a single experiment and, through ...

Turn off a light, save a life, says new study

March 20, 2019

We all know that turning off lights and buying energy-efficient appliances affects our financial bottom line. Now, according to a new study by University of Wisconsin-Madison researchers, we know that saving energy also saves ...

1 comment

Adjust slider to filter visible comments by rank

Display comments: newest first

not rated yet Sep 30, 2016
I'm pretty sure that in this case the increased biodiversity is the result of a low intraday variation of temperature gradient (compared to other latitudes/habitats).

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.