Introduction
Jessica Mozersky in Risky Genes, 2012
Despite this, there was an immediate interest in the 0.1 per cent difference, which researchers argued could translate into biomedically significant variability (Fujimura et al. 2008). Research into genetic variation between populations has focused on two main areas – medical genetics and population genetics. Medical research looks for genetic variation in disease and drug response among populations, while population research examines what genetic variation can tell us about the migration and ancestral history of various populations. Research projects in both these areas proliferate.3 One large and well-known project is the HapMap Project. HapMap is an international collaboration to find genetic similarities and differences between African, Asian and European populations that affect health, disease and drug response. They are using samples from the Yoruba in Nigeria to represent African ancestry, Han Chinese in Beijing and Japanese in Tokyo to represent Asian ancestry and from Utah residents to represent Northern and Western European ancestry. Currently the 1000 Genomes project is using whole genome sequencing on 1,000 individuals derived from more diverse groups including East Asians, West Africans, the Americas and Europe to provide a more comprehensive resource on human genetic variation.4
Bioengineering and Ethics
Howard Winet in Ethics for Bioengineering Scientists, 2021
With the discovery of Gregor Mendel’s 1866 paper in 1900, a mechanism for transmitting Darwin’s “variations” was finally in place. By 1903, microscopic techniques developed since 1866 helped reveal chromosomes, and the “gene” was named in 1909 (Millar et al. 1996). The Neo-Darwinism era had begun. It was concluded that it was the “natural selection” of this structure by the environment that drove biological evolution. When examined at the level of whole societies, population genetics could be applied to evolution. Natural selection began to be seen as a statistical problem in which risk and protective (from disease, etc.) factors had genetic determinants. Variation within a population can be considerable. Accordingly, the only way to conclude that a particular action had to be taken to stop agent A from reaching the population at large was to be “confident” about the correlation between the undesirable effect and agent A. A similar procedure needs to be followed in deciding if society would benefit from administering agent B to the population. Statistical methods for arriving at the required levels of confidence can be quite sophisticated. The techniques of previous statisticians like Galton were “modernized” by Karl Pearson (1857–1936) who developed the chi-square test (Millar et al. 1996). Pearson is considered a founder of 20th-century biological statistics (Millar et al. 1996).
LRs Considering Relatives as Alternate Contributors
Jo-Anne Bright, Michael D. Coble in Forensic DNA Profiling, 2019
As described in Chapter 3, Pr(E|Hp) = 1, as all the evidence is explained by the prosecution proposition. Under the defense proposition, we are calculating the conditional probability of a sibling being genotype 10,15 given the POI is a 10,15 at this locus. That is, Pr(sibling = 10,15|POI = 10,15). We consider all the different ways that siblings can share the same profile. This is easiest laid out in a table and we do so in Table 5.2. In the first row, we consider that both the 10 and 15 alleles are IBD (Z2), with probability ¼. In the second row, we consider the 15 allele as IBD and the 10 allele is not IBD but IBS. The probability of the brother having a 15 allele IBS depends on the subpopulation probability of that allele. In row three, the 10 allele is IBD with probability ¼ and the 15 allele is IBS with probability p15. Finally, in the last row, neither allele is IBD, with probability ¼, and they are IBS with probability 2p10p15. This is obtained by combining the probability of the 10 and 15 alleles within the subpopulation and a factor of two to take into account the order of alleles. In this example, we are using the product rule. Refer to Chapter 3 for further discussion about population genetic models.
Investigation of the genetic structure of Kabyle and Chaouia Algerian populations through the polymorphism of Alu insertion markers
Published in Annals of Human Biology, 2019
Hocine Badache, Sami Boussetta, Amel Benammar Elgaaeid, Lotfi Cherni, Houssein Khodjet El-khil
For each population we calculated allele frequencies by direct counting; we used Arlequin v3.5 package (Excoffier and Lischer 2010) to assess Hardy–Weinberg equilibrium by an exact test with Bonferroni’s correction (Guo and Thompson 1992) and to test population genetic structure through analysis of genetic distance (Fst), and Molecular Variance (AMOVA). Non-metric Multi-Dimensional scaling (NMDS) analysis (Kruskal 1964) was performed by means of Past software (Hammer et al. 2001) using the raw data of genetic distance matrix (Fst). To identify the genetic relationship between the studied populations of Algeria and other populations for comparison, the neighbour-joining (NJ) method based on gene frequencies was constructed using Phylip-3.695 software (Felsenstein 2005). Tree robustness was assessed using Bootstrap tests on 10 000 permutations (Felsenstein 1985). In order to describe possible variations in the correlation between genetic and geographic distances, we used GeDis 2.0 Software (Peña et al. 2009) based on the model of Harpending and Ward (Harpending and Ward 1982) to give a lineal relationship between heterozygosis and the distance to the centroid (Figure 1).
The association between leptin receptor polymorphism and suicidal behaviour in depressed adolescents
Published in International Journal of Psychiatry in Clinical Practice, 2020
S. Burak Acikel, Canan Eroglu, Asiye Ugras Dikmen, Ercan Kurar
General population genetics parameters – observed (Ho) and expected heterozygosities (He) values of each SNP and deviation from Hardy–Weinberg Equilibrium (HWE) – including the allele and genotype frequencies have been calculated by using GenAlEx6 (Peakall and Smouse 2012) package programme. The analysis of the data has been performed by using a Statistical Package programmer for Social Sciences (SPSS) 20.0 statistical software (Chicago, IL, USA). The chi-square test is used to analyse the differences between groups in categorical variables. When the normality of the distribution of variables is acceptable, the Student's t-test – or in other cases the Mann–Whitney U test – has been used to analyse the differences of psychiatric test scores between groups. Logistic and linear regression is conducted to assess the determinants of SPS scores. In this study, in linear regression model having a normal genotype is coded as ‘0’ and having a mutant allele (heterozygote and homozygote genotype) is coded as ‘1’ as an independent variable. By this way, the data are converted to ordinal. A two-tailed p-value of .05 is considered to be statistically significant.
High genetic complexity but low relatedness in Plasmodium falciparum infections from Western Savannah Highlands and coastal equatorial Lowlands of Cameroon
Published in Pathogens and Global Health, 2022
Ngoh Ines Atuh, Damian Nota Anong, Fru-Cho Jerome, Eniyou Oriero, Nuredin Ibrahim Mohammed, Umberto D’Alessandro, Alfred Amambua-Ngwa
The NWR and SWR attract migration from different parts of the country and from other countries including neighboring Nigeria, most especially traders. These regions are highly connected by various transportation networks, probably facilitating the sharing of infections. The SWR especially attracts tourist who come to experience its Atlantic coastal beaches, zoos and mount Cameroon sites. However, the role of human migration and its outcome on parasite population genetic structure and gene flow patterns remains unknown. Additionally, annual rainfall, temperature, topology and vegetation are particularly different between the highland grass field areas of the NWR and the coastal equatorial forest areas of the SWR [4]. It is not known if similar parasite genotypes indeed circulate across this geographical range. A few studies have examined the multiplicity of infection and/or allelic diversity of P. falciparum parasites from the South West by genotyping P. falciparum merozoite surface proteins (MSP1 and MSP2), and glutamine rich protein (GLURP) [7–10]. These studies reported significant differences in genetic diversity driven by altitude even for sites separated by only a few kilometers [8,10].
Related Knowledge Centers
- Adaptation
- Epistasis
- Population Structure
- Quantitative Genetics
- Statistical Inference
- Genetic Recombination
- Genetics
- Evolutionary Biology
- Speciation
- Dominance