An Evaluation of the Genetic Variation Within Selected Populations of Vaejovis Coahuilae Williams 1968 Using Mitochondrial Dna Analyses

ASU Author/Contributor (non-ASU co-authors, if there are any, appear on document)
Ramona Nichole Lopez (Creator)
Appalachian State University (ASU )
Web Site:
Mary U. Connell

Abstract: The species Vaejovis coahuilae Williams 1968 is the second most common scorpion species in New Mexico and Texas. This species is a generalist that can inhabit a wide array of habitats. Based on the reported range of this species, we predicted that it originated in northern Mexico and spread north through Texas and New Mexico. The aim of this study is to gain a better understanding of the historical dispersal pattern of the species V. coahuilae from Texas through New Mexico. A molecular approach was utilized to discover deeper relationships among populations of this species. Two partial sequences from the mitochondrial genome including the 16S rDNA and the cytochrome c oxidase subunit I (COI) gene are used to make a molecular comparison between populations. Isolated PCR products were sequenced using the LI-COR Global Edition IR2 DNA analyzer or at the DNA Core Facility at Cornell University using the Applied Biosystems Automated 3730 DNA analyzer. Three closely relates species were used as outgroups for sequence comparison. All sequences (39 total) were aligned using the BioEdit program to produce the finished products including a partial (360 bp) sequence of the mitochondrial 16S rDNA and a partial sequence (696 bp) of the COI gene. These two sequences were appended to produce a 1046 bp sequence that was also used to evaluate the dispersal pattern of V. coahuilae. These three data sets were analyzed separately using PAUP 4.0. One of the equally parsimonious trees was chosen for each data set to compute a 50% majority rule consensus tree and the topology was evaluated with 1,000 bootstrap replicates. Analysis of the 16S rDNA was mostly inconclusive producing a large polytomy but three populations from BBNP each fell out together and the populations from Albuquerque, San Antonio and one specimen from Deming grouped as a monophyletic subgroup. However, the arrangement of the tree suggests that all populations are equally related. Analysis of the COI gene was slightly more informative than the 16S rDNA analysis suggesting some geographically local populations to be more closely related to each other than to other populations. A large branch contains a polytomy with four branches; one of which contains one individual from GMNP and two individuals from the Roswell population; the other three branches contain individuals from BBNP. Outside of this polytomy are two branches containing a specimen from GMNP. The topology of both the COI/16s rDNA combined sequence data tree suggests possibly a high elevation specimen from GMNP (G3) has a more recently experienced gene flow with other populations. The branching pattern of the tree produced from the COI sequence data suggests the other specimen from GMNP collected at a much lower elevation on the eastern side of the mountain range has more recently experienced gene flow with populations in Roswell. In the topology of the COI tree and the combined sequence data tree the Albuquerque population appears more genetically related to populations from BBNP which represents the most northern and southern reaches of the sampled range. This suggests an accessible route for gene flow between the populations.

Additional Information

Lopez, R.N. (2010). An Evaluation of the Genetic Variation Within Selected Populations of Vaejovis Coahuilae Williams 1968 Using Mitochondrial Dna Analyses. Unpublished master's thesis. Appalachian State University, Boone, NC.
Language: English
Date: 2010