Analysis of Article on Genetic Differentiation of Scinax Treefrogs in South-eastern Brazil: [Essay Example], 868 words GradesFixer
exit-popup-close

Haven't found the right essay?

Get an expert to write your essay!

exit-popup-print

Professional writers and researchers

exit-popup-quotes

Sources and citation are provided

exit-popup-clock

3 hour delivery

exit-popup-persone
close
This essay has been submitted by a student. This is not an example of the work written by professional essay writers.

Analysis of Article on Genetic Differentiation of Scinax Treefrogs in South-eastern Brazil

Download Print

Pssst… we can write an original essay just for you.

Any subject. Any type of essay.

We’ll even meet a 3-hour deadline.

Get your price

121 writers online

blank-ico
Download PDF

The article I chose to write about for the second writing assignment focuses on Scinax treefrogs in south-eastern Brazil and how sea level incursions has shaped their genetic differentiation. I chose to write about this paper because I find it interesting how species near each other can be different from one another due to several factors.

The authors of the article focused their field study on three species belonging to the S. perpusillus group, in specific three populations from land-bridge islands in south eastern Brazil and five mainland populations in the Brazilian Atlantic Forest located in the Sao Paulo state. The study was conducted to investigate the genetic differentiation of the Scinax perpusillus treefrogs that is said to have resulted from Pleistocene refugia and sea level incursions. The purpose of the investigation was to understand how fragmentation in Pleistocene forest and incursions at sea level led to genetic differentiation. The purpose of the investigation was also to determine if the S. perpusillus group from the three islands; Ilha dos Porcos Pequena, Ilha da Queimada Grande and Ilha do Mar Virado sampled showed any signs of genetic drift or isolation.

The field study was carried on through January 2002 to April 2006, during that time six to thirty-seven individuals who were considered breeding adults were sampled from the three land-bridge islands. Tissue samples such as liver and toe clips were collected from individuals and placed in a 95% ethanol solution for later DNA extraction and genetic analyses. One of the first methods of the study was to use a DNeasy Blood and Tissue Kit to extract the genomic DNA from the preserved tissue collected. Once extracted the polymerase chain reaction technique was used to amplify and sequence a mitochondrial fragment that spanned the 16S and ND1 genes. At the end of the mitochondrial dataset there was a total of thirty samples as it is said that, “two to six individuals per locality were included. ” It was then found from the microsatellite dataset that there was a total of 149 samples.

In looking at microsatellite diversity as well as population and relatedness among, the authors tested for departures from Hardy-Weinberg equilibrium and evidence of linkage disequilibrium. In comparing relative diversity and divergence between mainland and island localities the software Arlequin 3. 1 was used. Arlequin 3. 1 was used to calculate the “pairwise genetic distance, mean number of alleles and the expected heterozygosity versus observed heterozygosity” of the sampling localities. Data gained from Arlequin 3. 1 such as, pairwise genetic distance was used to find the potential loss of genetic diversity among the three island populations with the mainland populations that are genetically closer to them.

A Mantel test was said to then be used to assess “the effects of drift on genetic differentiation across mainland and island population” which was setup with 1000 permutations and 500 bootstraps. Permutations and bootstraps were used to determine if the estimates of pairwise genetic distance between the localities correlated with the geographic distance. It was later said that if genetic drift and gene flow were at equilibrium than there would be a pattern of “isolation by distance where genetic differentiation is correlated with geographic distance between population”. It was also said that, “if genetic drift is the [only] force shaping genetic differentiation between populations to be elevated regardless of geographic distance”. In researching the microsatellite diversity, population structure and relatedness of the three species of S. perpusillus, fifteen alleles were said to be discovered from the eight loci. Though no evidence was found on the large allele dropout or as said “the scoring bias due to stutter, or null alleles across all populations”.

Overall, allelic richness was lower for the “island populations relative to their mainland counterparts and the expected heterozygosity was significantly lower only on Ilha do Mar Virado”. As Ilha Mar Virado has the lowest expected relatedness intervals from the three islands. It was concluded that the estimation of genetic divergence and geographic did not correlate among the three islands and their two closest mainland populations. There was also no correlation significant enough between the “mean heterozygosity and genetic divergence between island populations and the closet mainland populations”. At the end of the study the authors concluded that out of the three islands the only one that supports a Scinax island population is Ilha dos Porcos Pequena. This is said to be due to it forming a “monophyletic lineage in the mitochondrial phylogeography” as well as showing “no signs of introgression with mainland populations” regarding the microsatellite analyses. Though the species in Porcos Pequena are genetically divergent from the neighboring mainland the ones from Ilha do Mar Virado and Ilha da Queimada Grande are not genetically differentiated from that of their neighboring mainland.

At the end the authors stated that, “they detected a significant pattern of isolation by distance between mainland populations but not between island populations and mainland populations” which is said to suggest that genetic variation in the island populations has to do with genetic drift. The main conclusion agreed upon by the authors was that, “variation in genetic signatures across the three islands indicates that the populations experienced different demographic processes after marine incursions fragmented the distribution of the S. perpusillus group”.

Remember: This is just a sample from a fellow student.

Your time is important. Let us write you an essay from scratch

100% plagiarism free

Sources and citations are provided

Find Free Essays

We provide you with original essay samples, perfect formatting and styling

Cite this Essay

To export a reference to this article please select a referencing style below:

Analysis of Article on Genetic Differentiation of Scinax Treefrogs in South-eastern Brazil. (2020, July 14). GradesFixer. Retrieved January 14, 2021, from https://gradesfixer.com/free-essay-examples/analysis-of-article-on-genetic-differentiation-of-scinax-treefrogs-in-south-eastern-brazil/
“Analysis of Article on Genetic Differentiation of Scinax Treefrogs in South-eastern Brazil.” GradesFixer, 14 Jul. 2020, gradesfixer.com/free-essay-examples/analysis-of-article-on-genetic-differentiation-of-scinax-treefrogs-in-south-eastern-brazil/
Analysis of Article on Genetic Differentiation of Scinax Treefrogs in South-eastern Brazil. [online]. Available at: <https://gradesfixer.com/free-essay-examples/analysis-of-article-on-genetic-differentiation-of-scinax-treefrogs-in-south-eastern-brazil/> [Accessed 14 Jan. 2021].
Analysis of Article on Genetic Differentiation of Scinax Treefrogs in South-eastern Brazil [Internet]. GradesFixer. 2020 Jul 14 [cited 2021 Jan 14]. Available from: https://gradesfixer.com/free-essay-examples/analysis-of-article-on-genetic-differentiation-of-scinax-treefrogs-in-south-eastern-brazil/
copy to clipboard
close

Sorry, copying is not allowed on our website. If you’d like this or any other sample, we’ll happily email it to you.

    By clicking “Send”, you agree to our Terms of service and Privacy statement. We will occasionally send you account related emails.

    close

    Attention! this essay is not unique. You can get 100% plagiarism FREE essay in 30sec

    Recieve 100% plagiarism-Free paper just for 4.99$ on email
    get unique paper
    *Public papers are open and may contain not unique content
    download public sample
    close

    Sorry, we cannot unicalize this essay. You can order Unique paper and our professionals Rewrite it for you

    close

    Thanks!

    Your essay sample has been sent.

    Want us to write one just for you? We can custom edit this essay into an original, 100% plagiarism free essay.

    thanks-icon Order now
    boy

    Hi there!

    Are you interested in getting a customized paper?

    Check it out!
    Having trouble finding the perfect essay? We’ve got you covered. Hire a writer

    GradesFixer.com uses cookies. By continuing we’ll assume you board with our cookie policy.