gene flow

(noun)

the transfer of alleles or genes from one population to another

Related Terms

Examples of gene flow in the following topics:

  • Gene Flow and Mutation

    • An important evolutionary force is gene flow: the flow of alleles in and out of a population due to the migration of individuals or gametes.
    • Maintained gene flow between two populations can also lead to a combination of the two gene pools, reducing the genetic variation between the two groups.
    • Gene flow strongly acts against speciation, by recombining the gene pools of the groups, and thus, repairing the developing differences in genetic variation that would have led to full speciation and creation of daughter species.
    • Gene flow can occur when an individual travels from one geographic location to another.
    • Explain how gene flow and mutations can influence the allele frequencies of a population

  • Defining Population Evolution

    • Genetic variation in a population is determined by mutations, natural selection, genetic drift, genetic hitchhiking, and gene flow.
    • Because these individuals can share genes and pass on combinations of genes to the next generation, the collection of these genes is called a gene pool.
    • Five forces can cause genetic variation and evolution in a population: mutations, natural selection, genetic drift, genetic hitchhiking, and gene flow.
    • Gene flow is the exchange of genes between populations or between species.If the gene pools between two populations are different, the exchange of genes can introduce variation that is advantageous or disadvantageous to one of the populations.
    • Describe how the forces of genetic drift, genetic hitchhiking, gene flow, and mutation can lead to differences in population variation

  • Nonrandom Mating and Environmental Variance

    • Genes are not the only players involved in determining population variation.
    • If there is gene flow between the populations, the individuals will likely show gradual differences in phenotype along the cline.
    • Restricted gene flow, on the other hand, can lead to abrupt differences, even speciation.
    • Explain how environmental variance and nonrandom mating can change gene frequencies in a population

  • Allopatric Speciation

    • A geographically-continuous population has a gene pool that is relatively homogeneous.
    • Gene flow, the movement of alleles across the range of the species, is relatively free because individuals can move and then mate with individuals in their new location.
    • When populations become geographically discontinuous, that free-flow of alleles is prevented.
    • If two flying insect populations took up residence in separate nearby valleys, chances are individuals from each population would fly back and forth, continuing gene flow.
    • However, if two rodent populations became divided by the formation of a new lake, continued gene flow would be improbable; therefore, speciation would be probably occur.

  • Gene Duplications and Divergence

    • Gene duplication is the process by which a region of DNA coding for a gene is copied.
    • Duplicate genes are often immune to the selective pressure under which genes normally exist.
    • Many retrogenes display changes in gene regulation in comparison to their parental gene sequences, which sometimes results in novel functions.
    • Divergent evolution is usually a result of diffusion of the same species to different and isolated environments, which blocks the gene flow among the distinct populations allowing differentiated fixation of characteristics through genetic drift and natural selection.Divergent evolution can also be applied to molecular biology characteristics.
    • Both orthologous genes (resulting from a speciation event) and paralogous genes (resulting from gene duplication within a population) can be said to display divergent evolution.

  • Genetic Drift

    • Over successive generation, these selection pressures can change the gene pool and the traits within the population.
    • His offspring may continue to dominate the troop and pass on their genes as well.
    • His genes are passed on to future generation because of chance, not because he was the biggest or the strongest.
    • If one individual of a population of 10 individuals happens to die at a young age before leaving any offspring to the next generation, all of its genes (1/10 of the population's gene pool) will be suddenly lost.
    • Once an allele becomes fixed, genetic drift for that allele comes to a halt, and the allele frequency cannot change unless a new allele is introduced in the population via mutation or gene flow.

  • RNA Splicing

    • Gene expression is the process that transfers genetic information from a gene made of DNA to a functional gene product made of RNA or protein.
    • Genetic Information flows from DNA to RNA by the process of transcription and then from RNA to protein by the process of translation.
    • In eukaryotes, the gene contains extra sequences that do not code for protein.
    • Alternative splicing allows more than one protein to be produced from a gene and is an important regulatory step in determining which functional proteins are produced from gene expression.
    • Alternative splicing is a process that occurs during gene expression and allows for the production of multiple proteins (protein isoforms) from a single gene coding.

  • Epistasis

    • The B gene controls black (B_) vs. brown (bb) color, while the E gene controls yellow (ee) color.
    • Genes may also oppose each other with one gene modifying the expression of another.
    • Often the biochemical basis of epistasis is a gene pathway in which the expression of one gene is dependent on the function of a gene that precedes or follows it in the pathway.
    • In this case, the C gene is epistatic to the A gene.
    • Thus, the C gene is epistatic to the A gene.

  • Constructing an Animal Phylogenetic Tree

    • They consist of branches that flow from lower forms of life to the higher forms of life.
    • The ability of molecular trees to encompass both short and long periods of time is hinged on the ability of genes to evolve at different rates, even in the same evolutionary lineage.
    • Interestingly, 99% of the genes in humans and mice are detectably orthologous, and 50% of our genes are orthologous with those of yeast.
    • The hemoglobin B genes in humans and in mice are orthologous.
    • These genes serve similar functions, but their sequences have diverged since the time that humans and mice had a common ancestor.

  • Altered Gene Expression in Cancer

    • Cancer, a disease of altered gene expression, is the result of gene mutations or dramatic changes in gene regulation.
    • Cancer can be described as a disease of altered gene expression.
    • There are many proteins that are turned on or off (gene activation or gene silencing) that dramatically alter the overall activity of the cell.
    • This can be the result of gene mutation or changes in gene regulation (epigenetic, transcription, post-transcription, translation, or post-translation).
    • It can bind to sites in the promoters of genes to initiate transcription.