Genetic drift in mammals

Abstract

Genetic drift is the fortuitous occurrence of genetic events that when they become fixed modify the genome of populations. They can take the form of mutations of single nucleotides (SNPs), the insertion or deletion of short sequences (Indels) or the repetitions of short sequences (CNV i.e. copy number variants) or long insertions or deletion (structural modifications). Their frequency is 10-9 to 10-8 depending on the species, or 50 to 100 per birth in humans. The incidence of these de novo mutations is higher when the father is old at conception. It thus appears that genetic drift, which constitutes the initial element of evolution, has a very strong dynamics. Its intervention in the appearance or disappearance of some major phenotypes is complicated by the uncertainties about the genetic mechanisms in heritability which, paradoxically, are only partially understood.

Neuroimaging of Mouse Models of Alzheimer’s Disease

“…For example, those studies that found no significant changes in volumes reported manual analyses or data reported as percent of controls [ 104 , 108 , 114 ]. Finally, it is important to note the background and lineage of the 3xTg-AD mice (i.e., number of generations) used in the reported studies, as disease models are vulnerable to genetic drift [ 124 ].…”

Protein domains provide a new layer of information for classifying human variations in rare diseases

“…This information benefits greatly from the large-scale genome/exome sequencing projects and most people collect this information from gnomAD ( Koch, 2020 ) or population-specific databases, such as the ABraOM (Brazilian population) ( Naslavsky et al, 2017 ), TogoVar (Japanese population) ( Mitsuhashi et al, 2022 ) or Greater Middle East Variome (Middle East population) ( Scott et al, 2016 ). Nevertheless, human evolution has not allowed for genome saturation of variants and some of them are very rare in the population due to genetic drift ( Bach, 2019 ). Indeed, the chance appearance of a neutral variant not subject to a selection force will most likely result in its disappearance after several generations if the population is large enough, and only a few will be fixed in the population.…”