ANCESTRY IN LATIN AMERICA

 ANCESTRY IN LATIN AMERICA: BRAZIL STUDY

 

 

Name:

Course:

Institution:

Date:

 

 

Abstract

In this systematic review, the researcher sought to investigate the ancestry of populations in Latin America using the case of Brazil. In particular, the review focused on analyzing several pieces of empirical evidence on the genetic history of Brazilians. The study established that the Brazilian population is one of the world’s most heterogeneous populations, comprising of Europeans, Amerindians, and Africans. Multiple studies that have employed genetic markers and autosomal polymorphisms, particularly the electrophoresis protein markers and blood groups, indicate that regardless of their skin color, most of the Brazilians exhibit an overwhelming degree of European ancestry, significant scope of African ancestry, and a uniform degree of Amerindian ancestry. The implication of this empirical finding is that the genetic history of the Brazilian people is largely drawn from the European continent.

Keywords: ancestry, Brazil, Europeans, Amerindians, Africans, markers.

 

 

ANCESTRY IN LATIN AMERICA: BRAZIL STUDY

Introduction

Genetic association studies (GAS) are usually carried out to establish the specific genetic factors that underlie the vulnerability to complex diseases [1]. Coelho et al. [1] explain that the single nucleotide polymorphisms (SNPs) constitute the major genetic distinctions examined in GAS. Empirical evidence involving GAS and in particular SNP genotyping shows that the Northeastern Brazilian populations experience a significant influence of the European ancestry, followed by the African and Amerindian ancestries respectively [1-3]. Coelho et al.’s [1] study reveals that the dominance of European ancestry on the Northeastern Brazilian populations is 59.7% whereas Campanella et al.’s [2] research indicates that the predominance of the same ancestry in this population is 67.5%. Despite this disparity in the findings, the consensus of both studies is that the European ancestry has had a considerable impact on the people living in the north east region of Brazil.

It is worth pointing out that other than Coelho et al. [1] and Campanella et al.’s [2] studies, several other pieces of empirical evidence have demonstrated that it is not only the population in the north-eastern region of Brazil, but nearly in all of Brazil, whose ancestry is dominated by that of the Europeans and Africans [4-6]. Therefore, based on these studies, it can be inferred without any prejudice that the majority of the inhabitants in Northeastern Brazil, and Brazil in general, originated from the European continent or the African continent [4,5]. Nevertheless, this conclusion is not indicative of the assumption that the influence of the Amerindian and Asian ancestry in the Brazilian population is insignificant. It only implies that the ancestral origin of the vast majority of Brazilian inhabitants can be traced back to Europe and Africa respectively [6]. In other words, the genetic history of most Brazilians has its roots in both Europe and Africa, with the European ancestry showing much greater dominance than the African ancestry. The focus of this systematic review is to explore the ancestry in Latin America using the case study of Brazil.

Methodology

Search strategy and selection criteria

Typically, a systematic review focuses on identifying, appraising, and synthesizing various pieces of evidence that satisfy the eligibility criteria so as to effectively respond to a particular research question. The search strategy that was used in this systematic review followed the existing guidelines and, more importantly, the researcher formulated and adopted a search strategy that is highly detailed, reproducible, and documentable. The researcher conducted in-depth, objective, and reproducible search of a broad range of sources so as to identify as many relevant empirical pieces of evidence as possible. The search terms included “genomic,” “ancestry,” “Brazil,” “Latin America,” “admixture,” population,” “markers,” “genetic,” “allelic,” “frequencies,” “lineages,” “molecular,” “skin color,” and “screening.” The inclusion criteria employed in the search and selection strategy involved pre-test and post-test data. The search was limited to those articles published from 2007 to date. The exclusion criteria limited the search to the full-text articles that were presented in the scientific databases in English. The PRISMA diagram below (Figure 1) shows the various steps of the search and selection process.

            The quality control of the selected articles was carried out by two peer reviewers. They examined the accuracy of the quantitative and qualitative data as well as the research methodologies and the sample sizes using a customized Downs and Black checklist.

 

literature review1

Figure I
: PRISMA flow diagram

 

Results

Analysis of Skin Color in the Brazilian P