Evolution

the production of copies that become inserted into new positions in the genome

• Gene mutations (bp substitutions, point mutations, transition, transversion, frameshift mutations)
• Recombination
• Transposable elements --> cause changes

• synonymous: no efect on amino acid sequence of the protein (often in coding region)
• Nonsynonymous: result in amino acid substitutions

when homologous DNA sequences differ at two or more ase pairs -- generates new gene combinations

repeated origin of a particular mutation

mutation of a mutant allele back to the allele from which it arose (usually WT)

the variation in most phenotypic characters is this

based on several or many different genetic loci

redirect the development of one body segment into another (regulation of gene expression!)

if heterozygotes phenotype is precisely intermediate between the homozygotes

affect more than one character

description of its complement of chromosomes (number, size, shape, and internal arrangement)

unbalanced chromosome complement (often inviable or fails to develop properly)

changes in teh number of whole sets of chromosomes (more than 2 entire sets of homologous chromosomes)

arisen by the union of unreduced gametes of the same species

arisen by hybridization between closely related species

rearranged gene order from a loop and cross over

• pericentric = inversion that includes centromere
• paracentric = inversion that does not include centromere

two nonhomologous chromosomes may exchange sengemnts by breakage and reunion

• acrocentric = centromere near one end
• metacentric = centromere in middle

two nonhomologous acrocentric chromosomes undergo reciprocal translocation that they are joined into a metacentric chromosome

metacentric with acentric??? pg. 211

environmentally induced variation among individuals

effects of a mother on her offspring not from the gnes but to nongenetic influences (yolk in egg, maternal care, physiological condition of berthing)

when phenotypic differences not based on DNA sequence differences are transmitted among generations of dividing cells in multicellular organisms and also sometiems from parents to offspring (like DNA methylation)

variety of different phenotypic states that can be produced by a single genotype under different environmental conditions

offspring of phenotypically different parents can be reared together in a uniform environment

• 1. mating is random (panmictic)
• 2. population is infinitely large (no genetic drift)
• 3. genes are not added from outside the population (no gene flow)
• 4. genes do not mutate from one allele state to another (no mutation)
• 5. all individuals have equal probabilities of survival and of reproduction

mating among different populations (migration)

presence in a population of two or more variants (alleles or haplotypes)

locus/character that is not polymorphic

• inbreeding increases the proportion of homozygotes - mroe likely to get homozygote recessive (bad)
• Therefore, decline in components of fitness (survival, fecundity)

association/correlation between specific allels at two loci

no such association between specific alleles at the two loci

continous/metric varaition - fits a normal distribution

due to variation in phenotype

• sympatric = if distinct populations have overlapping geogrphic dddistributions so that they occupy the same area and frequently encounter each other
• parapatric = populations with adjacent but nonoverlapping ranges that come into contact
• allopatric = populations with spearated distributions

body size increases iwth increasing latitude

gradual change in a character or in allele frequencies over geogrpahic distance

phenotypes that are associated with a particular habitat, often in a partchy mosaic pattern

random fluctuation of alleles - p will eventually wander (drift) to either 0 or to 1 (no stabilizing force)

a genotype would increase rapidly in frequency because of linkage to an advantageous mutation that had ocurred at another locus

feature that fortuitously serves a new function

preadaptations that have been co-opted to serve a new function

when the heterozygote is said to be dominant

if heterozygote has lowest fitness

intermediate phenotype is fittest

if one extreme phenotype is fittest

if two or more phenotypes are fitter than the intermediates

(s) the amount by which teh fitness of a genotype differes from teh reference genotype (1-w)

• intensity of selection agaisnt the less fit genotype
• selective advantage of the fitter genotype

selection that maintains polymorphism

• 1. recurrent mutation producing deleterious alleles subject to weak selection
• 2. gene flow of locally deleterious alleles from other populations in which they are favored by selection
• 3. seletively neutrality (genetic ddrift)
• 4. maintenance of polymorphism by natural slection

opposing forces acting on polymorphisms - usually does not maintain polymorphisms

the rarer a phenotype is in teh population the greater its fitness

• the fitness of a genotype is greater the more frequent it is in the population
• whichever allele is initally more frequent will be fixed

reduction/elimination of DNA sequence variation in teh vicinity of a mutation that has been fixed by natural selection relatively recently