Scientists use Mitochondrial DNA to Identify Recently Diverged Mouse Lemur Lineages

5 04 2010
This image is copyrighted under the creative commons attribution license by Weisrock D.W., Rasoloarison R.M., Fiorentino I., Ralison J.M., Goodman S.M., et al. (2010) for the article “Delimiting Species without Nuclear Monophyly in Madagascar's Mouse Lemurs”. Appearing in PLoS ONE 5(3): e9883. doi:10.1371/journal.pone.0009883.

The island of Madagascar, showing the areas of sampling used in this study.

An international team of researchers has used mitochondrial DNA (mtDNA) to help distinguish between a group of Madagascar Mouse Lemurs who have recently begun to diverge.

One of the issues associated with delineating species that have recently diverged from common ancestors is that often there has not been sufficient time for the usual cues of speciation, such as morphological differences, reproductive isolation, and monophyly within the gene tree to have become settled and readily evident.  Writing in the online journal, PLoS One, seven scientists from the United States, Germany, and Madagascar used multiple lines of evidence from mtDNA and nuclear DNA (nDNA) to identify “cryptically diverged” population-level mouse lemur lineages from throughout Madagascar.  It is believed to represent the most thorough sample of mouse lemur species ever conducted.

The result was the identification of a large number of geographically-defined clades.  These were strongly supported by the initial mtDNA evidence, as well as additionally supported by nDNA patterns.  The clades thus identified, are also supported by population divergence estimates based on genealogical exclusivity estimates.  The paper concludes that “Mouse lemur lineage diversity is reflected in both a geographically fine-scaled pattern of population divergence within established and geographically widespread taxa, as well as newly resolved patterns of micro-endemism revealed through expanded field sampling into previously poorly and well-sampled regions.”

For more information, please see the original article at the following URL: http://www.plosone.org/article/info:doi/10.1371/journal.pone.0009883

Advertisements




Coastal Paleontologist Blogs on Early Seal Evolution

29 03 2010
This image is courtesy of Wikimedia Commons.  It is by Vivien Thiessen, and is licensed under the GNU Free Documentation License, Version 1.2 or any later version published by the Free Software Foundation; with no Invariant Sections, no Front-Cover Texts, and no Back-Cover Texts.

The comparative anatomy of an otariid seal and a phocid seal, both of which are discussed in Coastal Paleontologist’s blog piece.

The Coastal Paleontologist has a very interesting piece on early seal evolution.  It can be found at the following location:  Pinniped ancestry: the “Oligocene Seal” from South Carolina.

Following is the first paragraph from the blog, just as a teaser:

One of the most fascinating aspects of the study of marine mammals are the origins of the land to sea transition in various groups. Often marine mammals are so adapted for marine existence, that it is difficult to identify what group (fossil or modern) they descended from. Such has been the case with the origin of whales, for example. While I’m certainly interested in cetaceans, there has been a ton written about them, and I’m currently more intrigued by pinnipeds.