Mr. Mathieu
Period 2
Author: unknown; Source: Wildlife Conservation Society
Published: January 9, 2014
Link: http://www.sciencedaily.com/releases/2014/01/140109003754.htm
Summary:
According to authors from the Wildlife Conservation Society, the American Museum of Natural History's Sackler Institute for Comparative Genomics, the University of Lisbon, and other groups, the clymene dolphin species was developed through the process of natural hybridization. Hybridization is when members of two distinct species produce offspring that are a new species. This has been occurring naturally between dolphins and producing unique dolphin species. The clymene dolphin is a hybrid of the spinner and striped dolphins. Ana R. Amaral, lead author of the study and research associate at the American Museum of Natural History said, "This [study] also provides us with an excellent opportunity to better understand the mechanisms of evolution." Taxonomists used to believe that the clymene species was a subspecies of the spinner dolphin, but in 1981, it was established as a separate species. In the study, scientists took the mitochondrial and nuclear DNA from clymene, spinner, and striped dolphins. For data, they amplified 6 nuclear DNA markers and 1 mitochondrial DNA marker in order to see the evolutionary relationship between the three species. The nuclear genome was more alike to the spinner dolphin, and yet, the mitochondrial genome was more similar to the striped dolphin. Continued hybridization could be possible.
This article connects to the unit of evolution, as the scientists want to use the data from the study, and the study itself in order to be able to have a deeper understanding of evolution. One way to test the evolutionary relationship between organisms is molecular, or genetic analysis. You can get the exact and specific data needed to see the clear relationships that a certain organism has with another organism. In their study, they examined the DNA of the dolphins to see the correlation between the clymene, spinner, and striped dolphins. We also have been doing DNA amplification in our own labs as they have done to study these dolphins, using PCR to amplify the extracted DNA and then visualizing it through Gel Electrophoresis. The concept of hybrids is something we have also discussed in class, when talking about how individuals from different species should not be able produce fertile offspring.
We learned that when two groups of organisms are identified as two different species it implies that they cannot mate and produce fertile offspring. But how is it possible that these two separate species have interbred and produced a whole new species of dolphins that are fertile?
ReplyDeleteHybridization leading to a whole new fertile species is quite rare, especially in mammals. According to some scientists, there are two requirements for having this happen: the hybrids have to be as fit as the two original species, so that they can put themselves into a stable environmental niche, and the hybrids have to only mate with others of their species, not with any of the original species' members. To have both of these requirements met is extremely rare.
ReplyDeleteAlso, though hybridization is extremely rare in mammals, cetaceans (marine mammals such as whales, dolphins, and porpoises) have been observed to have produced a few hybrid species, both naturally and in captivity. Scientists believe that the reason is that these cetaceans have close numbers of chromosomes even in the different species, so they could produce fertile hybrids more easily.
This link is an interesting article that also addresses the topic of the clymene dolphin's origins and how this unexpected fertile hybrid species could be possible:
http://news.nationalgeographic.com/news/2014/01/140111-hybrid-dolphin-species-ocean-animal-science/