Zoologist Ben Evans, of McMaster University in Hamilton, and a team of researchers have discovered six new species of African clawed frog (Xenopus). All six new species are relatively small (approximately 5 cm) and were found in West and sub-Saharan Africa.
African clawed frogs are highly aquatic, living in slow moving or stagnant water. Characteristically they have streamlined and flattened bodies, a vocal organ specialised for underwater sound production, lateral line organs, claws on the first three toes (inner) and fully webbed toes. African clawed frogs are widely used as a model organism for biological research including developmental biology, cell biology, toxicology, neuroscience and for modelling human disease and birth defects. They also provide a unique system for analyses of genome evolution and whole genome duplication in vertebrates, as most clawed frog species are polyploid ie they have multiple sets of DNA due to genome duplication.
The discovery of these six new species, increases the number of known clawed frog species to...
Large sea otter populations once ranged from Northern Japan all the way around the Northern Pacific Rim to Baja California. However, in 1741 when the fur trade began, their numbers started to rapidly decline. The pelts of sea otters were so in demand that sea otter populations were driven to near extinction by the end of the 19thcentury. In 1911 sea otters were protected by the International Fur Seal Treaty but for some populations this was already too late.
In the Kuril Islands, Kamchatka Peninsula, Aleutian Islands, South-Central Alaska and California the small remaining populations began to grow. Some populations have returned to their historical population sizes but others, such as the population in California, have grown more slowly. Annabel Beichman, a PhD student at UCLA, together with Monterey Bay Aquarium are leading the effort to aid the recovery of the sea otters. They plan the first ever sequencing of the sea otter genome.
The extreme decline, to a very small size,...
Even at our most peaceful time of the day, when we are calm, not moving, in silence, no matter how quiet our body looks, there is something completely different going on inside us. In our body there are thousands of chemical reactions going on, numerous biochemical routes working at the same time and for the most part they are all perfectly balanced. This dynamic equilibrium is our own point in evolution, where we, as an individual or a group, fit into our environment.
In every balanced system, affecting one of the components may cause an imbalance that puts at risk the whole group integrity.
Of all biomolecules or cell components, DNA is probably the most challenging and interesting from a biological point of view. DNA constitutes the genetic instructions for the development, functioning and reproduction of all known living organisms and therefore genetically determines who or what we are.
It is thus with a mixture of trepidation and excitement that the ready availability...
Along evolution, genes mutate to allow adaptation to environmental conditions. Scientists from Penn State University, Nanyang Technological University in Singapore, and the University of Chicago have recently identified the genetic changes that helped the woolly mammoth survive in the Arctic.
Comparing the complete set of genes of the woolly mammoth with their closest living relatives, the Asian elephant and the African elephant, scientists have identified some of the mutations responsible for the adaptation of the extinct wooly mammoth to extreme cold. Interestingly, most of these mutations are in genes involved in hair development, temperature sensing and body fat storage and metabolism, all of them crucial to survive in harsh arctic conditions.
One of the most interesting and challenging aspects of this study is that some of the computational predictions were verified by laboratory experiments. For instance, it has been confirmed that a mammoth-specific change in a protein called TRPV3, related to temperature sensation, hair growth, and body-fat storage, modifies the protein's response...
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