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Developmental biology - Evolutionary Genetics

New species arise from rapid mitochondrial evolution

How mitonuclear incompatibilities might drive speciation...

Genetic research at Oregon State University sheds new light on how isolated populations of the same species evolve and move toward reproductive incompatibility before becomming a unique separate species.
Scientists sequenced the entire genome of a Pacific tidepool crustacean called Tigriopus californicus which is used as a model species to study differentiation based on geographic separation - an early stage of when one species becomes multiple species.

Researchers examined the co-evolution of both mitochondrial and nuclear genes in this species. Mitochondria act as a cell's power plant, generating adenosine triphosphate, or ATP - a source of chemical energy. As in all animals, most of a T. californicus cell's genes are in its nucleus, but some are also in the mitochondria.
"The mitochondria organelle contains a small chromosome with only 37 genes, which are absolutely essential to its metabolism. In order for ATP to be produced properly in a cell, a few hundred other genes encoded in the nucleus must interact directly with those 37 mitochondrial genes. Mutations in mitochondrial genes may cause subpar interactions, thus reduce metabolic performance."

Felipe Barreto PhD, Assistant Professor, Integrative Biology, OSU's College of Science the study's corresponding author.

T. californicus populations along the Pacific coast of North America have mitochondrial genes that differ widely from one population to the next - with lots of related mutations.

"As a result, hybrid offspring between populations suffer from lowered fitness in the form of lower fecundity, slow development and lower ATP production as determined by several previous experiments," Barreto added.

Barreto and collaborators from the University of California, San Diego, the University of Southern California and the University of North Carolina, used molecular statistical models in order to screen eight T. californicus populations and detect which genes might be incompatible between populations. His intention?: "Those genes may therefore be candidate genes for understanding how different populations become incompatible and possibly eventually become different species."

The findings are published this week in Nature Ecology and Evolution.

Genomes of eight populations of the copepod Tigriopus californicus show a correlation between rapid mitochondrial evolution and compensatory nuclear evolution, suggesting that mitonuclear incompatibilities might drive speciation in this system.

Authors: Jerome H. L. Hui.

Simon F.S. Li Marine Science Laboratory, Partner State Key Laboratory of Agrobiotechnology, School of Life Sciences, The Chinese University of Hong Kong, Hong Kong.

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Jul 17, 2018   Fetal Timeline   Maternal Timeline   News   News Archive

Tigriopus californicus is a species of intertidal crustacean that lives on the Pacific coast
of North America. They are the subject of numerous scientific studies ranging
from ecology and evolution to neurobiology. Source: Wikipedia.

Phospholid by Wikipedia