Mutational meltdown

Mutational meltdown

Mutational meltdown refers to the process by which a small population accumulates harmful mutations, which leads to loss of fitness and decline of the population size, which may lead to further accumulation of deleterious mutations due to inbreeding depression. A population experiencing mutational meltdown is trapped in a downward spiral and will go extinct if the phenomenon lasts for some time. Usually, the deleterious mutations would simply be selected away, but during mutational meltdown, the number of individuals thus suffering an early death is too large relative to overall population size so that mortality exceeds the birth rate.

The accumulation of mutations in small populations can be divided into three phases. In the second phase a population starts in mutation/selection equilibrium, mutations are fixed at a constant rate through time, and the population size is constant because the fecundity exceeds mortality. However, after a sufficient number of mutations have been fixed in the population, the birth rate is slightly less than the death rate, and the population size begins to decrease. The smaller population size allows for a more rapid fixation of deleterious mutations, and a more rapid decline of population size, etc.

See also

Further reading

Wikimedia Foundation. 2010.

Look at other dictionaries:

  • Small population size — Populations with small population size behave differently to larger populations. Often this has various harmful consequences for the survival of that population.Demographic effectsThe influence of stochastic (random) variation in demographic… …   Wikipedia

  • Muller's ratchet — Illustration of chromosome crossover during genetic recombination In evolutionary genetics, Muller s ratchet (named after Hermann Joseph Muller, by analogy with a ratchet mechanism) is the process by which the genomes of an asexual population… …   Wikipedia

  • Plant evolutionary developmental biology — For a more ecological discussion on the evolution of plant morphology, refer to Evolutionary history of plants Evolutionary developmental biology (evo devo) refers to the study of developmental programs and patterns from an evolutionary… …   Wikipedia

  • Population genetics — is the study of the allele frequency distribution and change under the influence of the four evolutionary forces: natural selection, genetic drift, mutation and gene flow. It also takes account of population subdivision and population structure… …   Wikipedia

  • List of biology topics — Biology is the study of life and its processes. Biologists study all aspects of living things, including all of the many life forms on earth and the processes in them that enable life. These basic processes include the harnessing of energy, the… …   Wikipedia

  • Evolutionary biology — is a sub field of biology concerned with the origin of species from a common descent, and descent of species; as well as their change, multiplication, and diversity over time. Someone who studies evolutionary biology is known as an evolutionary… …   Wikipedia

  • List of evolutionary biology topics — This is a list of topics in evolutionary biology and evolution. See also: List of biology topics, List of biochemistry topics, NOTOC A abiogenesis adaptation adaptive radiation allele allele frequency allopatric speciation altruism Archaeopteryx… …   Wikipedia

  • Extinction vortex — Extinction vortices are a class of models through which conservation biologists, geneticists and ecologists can understand the dynamics of and categorize extinctions in the context of their causes. Developed by M. E. Gilpin and M. E. Soulé in… …   Wikipedia

  • Functional extinction — is the extinction of a species or other taxon such that:#it disappears from the fossil record, or historic reports of its existence cease; [ Extinctions in Near Time: Causes, Contexts, and Consequences 1999. Edited by R.D.E. MacPhee, Hans Dieter… …   Wikipedia

Share the article and excerpts

Direct link
Do a right-click on the link above
and select “Copy Link”

We are using cookies for the best presentation of our site. Continuing to use this site, you agree with this.