Shaina Sikka
Mr. Mathieu
Period 2
January 14th, 2014
Author: Unknown. Materials provided by Wildlife Conservation Society
Published: January 9th, 2014
Article URL: http://www.sciencedaily.com/releases/2014/01/140109003754.htm
Summary:
Found in the Atlantic Ocean, the Clymene Dolphin is a sleek marine mammal that can grow up to seven feet in length. The mammal was originally thought to be a subspecies of the Spinner Dolphin, but through genetic analysis, the Clymene Dolphin was found to be a fertile natural hybridization of two closely related dolphin species, the Striped Dolphin and the Spinner Dolphin. It is the first documented result of natural hybridization in marine mammals. To find proof that the Clymene originated from the spinner and striped dolphins, the American Museum of Natural History’s Sackler Institute for Comparative Genomics examined the nuclear and mitochondrial DNA from skin samples from both free-ranging and dead dolphins of all three species. The researchers chose certain markers in both DNA samples to analyze the evolutionary relationship between the Clymene dolphin and its closest relatives. The results showed that the mitochondrial genome of the Clymene Dolphin was closest to the Striped Dolphin, while the nuclear genome resembled the Spinner Dolphin. Therefore, the occurrence is best described as natural hybridization. Researchers say that more hybrids may form, yet at low levels, however this occurrence will be an opportunity to extend the understanding of the mechanisms of evolution.
Found in the Atlantic Ocean, the Clymene Dolphin is a sleek marine mammal that can grow up to seven feet in length. The mammal was originally thought to be a subspecies of the Spinner Dolphin, but through genetic analysis, the Clymene Dolphin was found to be a fertile natural hybridization of two closely related dolphin species, the Striped Dolphin and the Spinner Dolphin. It is the first documented result of natural hybridization in marine mammals. To find proof that the Clymene originated from the spinner and striped dolphins, the American Museum of Natural History’s Sackler Institute for Comparative Genomics examined the nuclear and mitochondrial DNA from skin samples from both free-ranging and dead dolphins of all three species. The researchers chose certain markers in both DNA samples to analyze the evolutionary relationship between the Clymene dolphin and its closest relatives. The results showed that the mitochondrial genome of the Clymene Dolphin was closest to the Striped Dolphin, while the nuclear genome resembled the Spinner Dolphin. Therefore, the occurrence is best described as natural hybridization. Researchers say that more hybrids may form, yet at low levels, however this occurrence will be an opportunity to extend the understanding of the mechanisms of evolution.
Connection:
This article relates to our study on evolution. In lesson 15.1, we learned that species are populations whose members have the ability to breed with one another and produce fertile offspring, and that members of one species cannot successfully interbreed with members of another species. The natural hybridization of the two related dolphin species is an exception to definition of species. We know that different species are unable to produce fertile offspring, if any. Yet, in this case two closely related dolphin species did so. In addition, in lessons 14.2 and 15.4 we learned that molecular biology can be used to study the relationships between species. The more genes and protein sequences match up, the more closely related the species are. This article uses the method of molecular biology to determine the relatedness of the three dolphins species by sequencing and comparing their mitochondrial and nuclear genomes.
Why is it that hybridization occurs so much less frequently in marine mammals than land mammals?
ReplyDeleteHow does having the mitochondrial genome closer to the striped dolphin and the nuclear genome closer to the spinner dolphin affect the phenotype of the Clymene Dolphin?
ReplyDeleteI do not know the exact answer to this question, since I found nothing when I researched for an answer. I can infer, from my knowledge of biology from previous units that the the DNA in the nucleus relates to phenotype since the DNA goes through transcription and translation and then it sequences the proteins affect phenotypes. Therefore, the Clymene's phenotype resembles the spinner dolphin the most because of it's close match to the spinner dolphin's nuclear genome. For more information on the two genomes you can visit: http://www.nfstc.org/pdi/Subject09/pdi_s09_m02_01.htm
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