Population genetics basis of evolutionary change Flashcards
(19 cards)
Define the term heritable
characteristics passed on from parents to offspring
Define the term anagenesis
- between-generation change within a single lineage –> transformation
- due to genetic divergence
Define the term cladogenesis
division of a single lineage due to genetic divergence –> splitting/branching
What is meant by the term microevolution?
- refers to within-species evolution
- includes processes leading to speciation
What is meant by the term macroevolution?
- speciation events - splitting of lineages
- subsequent divergence of species and higher taxa
What is meant by junk DNA?
- sequences within introns of genes and those between genes
- assumed not to be subject to natural selection
What is meant by the term ‘polymorphic locus’
when nucleotide sequences differ at the same locus on the paired chromosomes
What does the phenotype comprise of?
- external appearance
- internal structures/tissues
- intracellular structures
- protein/polypeptides
What is the difference between continuous and discontinuous traits?
continuous:
- intermediates exist between 2 extremes
- many gene loci involved and many alleles involved
discontinuous:
- no intermediates exist
- one of few gene loci involved and only a few alleles involved
What is meant by population genetics?
processes that create genetic variation
What is meant by genetic drift?
random changes in allele frequencies within a population
What is meant by ‘bottleneck’
random reduction in the number of breeders
What is the effect of genetic drift?
- loss of heterozygosity
- inbreeding
What is the difference between linkage equilibrium and linkage disequilibrium
linkage disequilibrium - non-random association between loci
linkage equilibrium - random association between loci
How to calculate linkage disequilibrium
A-B or A-b (1:1) –> no
A-B > A-b (>1:1) –> yes
What is meant by adaptive evolutionary change
under natural conditions, the genetic variant conferring higher fitness increases in relative abundance within the gene pool
What is meant by selectively neutral genes
genes whose frequencies are not influences by natural selection
What is meant by pleiotropy
multiples effects of an individual gene
Lis the types of constraints upon evolutionary change
- insufficient genetic variation exists in the gene pool
- no selection pressure operating
- sufficient selection pressures but there exists constraint upon changing the blueprint of an organism
