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Lecture

Genetic Variation in Populations

In course

BIO-373: Genetics and genomics

The theoretical part of this course covers classical genetics and contemporary genomics. Because bioinformatics has become important for genomic research, the course also includes practical applications to genomic analyses using Python, including group pro ...

Description

This lecture covers the study of genetic variation in populations, including the gene pool concept, detection of genetic variation, neutral theory, Hardy-Weinberg law, and its applications in human populations. It also discusses natural selection, mutation, migration, genetic drift, and non-random mating, with examples and calculations for allele and genotype frequencies.

Instructors (2)

Jacques Fellay

Jacques Fellay is a medical scientist with expertise in infectious diseases and human genomics. He obtained his MD from the University of Lausanne in 2002 and his PhD from University of Utrecht. After a clinical training in infectious diseases in Switzerland and a 4-years postdoctoral fellowship at Duke University, he joined the EPFL in April 2011 with an SNF Professorship. On top of his EPFL affiliation, Jacques is also Head of Precision Medicine at the University Hospital (CHUV) in Lausanne, Group Leader at the Swiss Institute of Bioinformatics, and Co-director of the Health2030 Genome Center at Campus Biotech in Geneva.

Bart Deplancke

Official source

Ontological neighbourhood

Biology

Genetics: Population genetics

Related concepts (32)

Allele frequency

Allele frequency, or gene frequency, is the relative frequency of an allele (variant of a gene) at a particular locus in a population, expressed as a fraction or percentage. Specifically, it is the fraction of all chromosomes in the population that carry that allele over the total population or sample size. Microevolution is the change in allele frequencies that occurs over time within a population. Given the following: A particular locus on a chromosome and a given allele at that locus A population of N individuals with ploidy n, i.

Allele

An allele (UKˈæliːl, əˈliːl; USəˈliːl; modern formation from Greek ἄλλος állos, "other") is a variation of the same sequence of nucleotides at the same place on a long DNA molecule, as described in leading textbooks on genetics and evolution. The word is a short form of "allelomorph". "The chromosomal or genomic location of a gene or any other genetic element is called a locus (plural: loci) and alternative DNA sequences at a locus are called alleles.

Genetic drift

Genetic drift, also known as random genetic drift, allelic drift or the Wright effect, is the change in the frequency of an existing gene variant (allele) in a population due to random chance. Genetic drift may cause gene variants to disappear completely and thereby reduce genetic variation. It can also cause initially rare alleles to become much more frequent and even fixed. When few copies of an allele exist, the effect of genetic drift is more notable, and when many copies exist, the effect is less notable.

Natural selection

Natural selection is the differential survival and reproduction of individuals due to differences in phenotype. It is a key mechanism of evolution, the change in the heritable traits characteristic of a population over generations. Charles Darwin popularised the term "natural selection", contrasting it with artificial selection, which is intentional, whereas natural selection is not. Variation exists within all populations of organisms. This occurs partly because random mutations arise in the genome of an individual organism, and their offspring can inherit such mutations.

Genetic variation

Genetic variation is the difference in DNA among individuals or the differences between populations among the same species. The multiple sources of genetic variation include mutation and genetic recombination. Mutations are the ultimate sources of genetic variation, but other mechanisms, such as genetic drift, contribute to it, as well. Genetic variation can be identified at many levels. Identifying genetic variation is possible from observations of phenotypic variation in either quantitative traits (traits that vary continuously and are coded for by many genes (e.

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