Evolutionary biology Flashcards
Phenotypic plasticity
Phenotypic plasticity is the ability of an individual genotype to produce different phenotypes in response to the environment. Since plasticity is a property of the individual, it is often hailed as a rapid-response mechanism that will enable organisms to adapt and survive in our rapidly changing world (sometimes termed ‘plastic rescue’)
Adaptation
Long-term irreversible responses, usually requiring de novo mutations in the genome or species sorting
Contact Zone
a geographic area where two divergent populations or closely related species overlap in distribution and potentially hybridise; the term ‘contact zone’ is more appropriate than ‘hybrid zone’ unless it is clear that hybrids are produced
Introgression
When there is some gene flow from one population (say, population A) to the other (say, population B). We would say that population A introgresses into population B. Incorporation of genetic material from one species or population into the genome of another species or population by hybridisation followed by repeated backcrossing
Admixture
If gene flow goes both ways, then the two populations A and B are admixing
Selective Sweep
A process by which a new advantageous mutation eliminates or reduces variation in linked neutral sites as it increases in frequency in the population (Nielsen et al., 2005).
A process through which a new beneficial mutation that increases its frequency and becomes fixed in the population leads to the reduction or elimination of genetic variation among nucleotide sequences that are near the mutation
Isolation by distance (IBD)
is a term used to refer to the accrual of local genetic variation under geographically limited dispersal. The IBD model is useful for determining the distribution of gene frequencies over a geographic region. Both dispersal variance and migration probabilities are variables in this model and both contribute to local genetic differentiation.
Isolation by distance is usually the simplest model for the cause of genetic isolation between populations.
Synonymous mutation/substitution
A synonymous mutation is a change in the DNA sequence that codes for amino acids in a protein sequence, but does not change the encoded amino acid. Due to the redundancy of the genetic code (multiple codons code for the same amino acid), these changes usually occur in the third position of a codon.
Nonsynonymous mutation/substitution
A nonsynonymous substitution is a nucleotide mutation that alters the amino acid sequence of a protein. Nonsynonymous substitutions differ from synonymous substitutions, which do not alter amino acid sequences and are (sometimes) silent mutations.
Mendelian trait
Mendelian traits are determined by a single gene and inherited in a simple fashion that follows the laws of inheritance described by Mendel. Aka they are monogenic traits
Polygenic traits
Polygenic traits are much more complex than Mendelian traits. Rather than being shaped by a single gene alone, a polygenic trait is influenced by multiple genes. While the individual genes all exhibit Mendelian patterns of inheritance, the trait itself does not, because so many different genes are involved in shaping it.
Adaptive divergence
Genetically based phenotypic differences that improve local fitness
Dispersal
Movement of individuals between populations
Gene flow
Movement of genes between populations
Epistasis
Occurs when the effect of a certain allele of a gene at a locus ‘A’ depends on the alleles of another gene present at locus ‘B’
