Introduction
For a long time, scientists have believed that intra-specific variation in animals based on geographical patterns and variables has a somewhat close link to the process of speciation. For example, several populations or individuals of a particular species of animals which occur in differentiated areas have been discovered to diverge due to morphological conditions, calls or color (Wang, 2011). These variations which occur phenotypically may have a relation to distinct geographical terminologies including natural selection, sexual selection or genetic drift (Wang, 2011). With an objective to carry out a thorough investigation on the intraspecific genetic divergence incorporated with the phenotypic diversification in a species known as Oophagagranulifera , a research was conducted through an analysis of aspects such as phylogeographical patterns, the structure of the population, coloration and traits all of which were deemed potential elements which had an involvement in reproductive isolation.
Methodology
The analysis incorporated the use of mitochondrial genes cytochrome b and 16S. The two markers then got sequenced in 28 individuals who were from 10 populations, and 16 other individuals belonging to 9 communities respectively. Concerning population structure, an analysis was done based on seven polymorphic microsatellite loci in individuals ranging from seven to fifteen and who belonged to 11 populations (Wang, 2011). This was made possible by basing the hypotheses on the maximum likelihood of occurrences and Bayesian analyses. Measurements then got taken on the color phenotypes of a total of 189 frogs and the reflectance spectra of 15 frogs from a total of five populations. Advertisement calls of a total of 59 males were then recorded and measurement of the morphological variables also taken.
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Major results
It got found out that the distribution concerning color proved to be asymmetrical in comparison to the genetic variation. The southern lineage had included monomorphic populations which were red. The northern descent, on the other hand, was characterized by red green and polymorphic populations. There was a distinct, though the slight difference between the two lineages with regards to advertisement calls and morphology (Wang, 2009). A confirmation from microsatellites stated that there was proof of clear inter-lineage divergence (Brusa, 2012). Further analysis revealed that the northern lineage got characterized by a distinct difference between the red and green morphs in terms of advertisement calls, body size, and pulse rate. Additionally, no simple genetic or color cline was found, with regards to color transition.
Conclusion
From the results, we can conclude that Oophagagranulifera has undergone evolution which has led to the development of two genetic lineages. From the observation that got made regarding the reduction in gene flow and diversification in both morphology and advertisement calls, it is clear that this was proof of reproductive isolation taking place between the southern and northern lineages. Evidence of gene flow within the color transition region got ruled as a conclusion of the finding whereby gradual intermediate morphs and the structure of the population got observed (Brusa, 2009) The existing divergence between the red and green morphs concerning both morphology and calls is an indication of the possibility of assortative mating. Additionally, the deficiency in genetic diversification among all the color morphs and interconnectedness among genes of the varied populations whose role is to define a transition on color serves as concrete proof of recent development of the aspect of color diversification in this particular species
References
Brusa, O., Bellati, A., Meuche, I., Mundy, N. I., & Pröhl, H. (2012). Divergent evolution in the
polymorphic granular poison-dart frog, Oophaga granulifera: genetics, coloration, advertisement calls, and morphology. Journal of Biogeography , 40 (2), 394-408. doi:10.1111/j.1365-2699.2012.02786.x
Wang, I. J., & Summers, K. (2009). Highly polymorphic microsatellite markers for the highly
polymorphic strawberry poison-dart frog and some of its congeners. Conservation Genetics , 10 (6), 2033-2036. doi:10.1007/s10592-009-9887-z
Wang, I. J. (2011). INVERSELY RELATED APOSEMATIC TRAITS: REDUCED
CONSPICUOUSNESS EVOLVES WITH INCREASED TOXICITY IN A POLYMORPHIC POISON-DART FROG. Evolution , 65 (6), 1637-1649. doi:10.1111/j.1558-5646.2011.01257.x
