Exam 4 Flashcards
how is relative fitness (W) calculated?
Wx = (# of offspring of x) / (# of offspring of the one with the highest fitness)
gene with the highest reproductive value (most offspring) will always have a fitness of W = 1.0 and other fitness values will be determined relative to that one
what is a population?
the term for a group of organisms of the same species that can interbreed and live in an isolated group
monomorphic vs polymorphic vs monogenic vs polygenic
monomorphic: a gene that has only one allele
polymorphic: a gene with two or more alleles
monogenic: controlled by a single gene
polygenic: controlled by more than one gene
what is directional selection and what is an example?
when the survival of one extreme phenotype or the other is favored, dark winged butterflies are favored in dark environments as opposed to light winged ones
what is balancing selection and what is an example?
when the maintenance of two or more alleles are favored, heterozygotes with sickle cell anemia are more likely to survive when infected with malaria, or pollinators visiting more rare flower colors more which keeps one color from becoming too common or rare
what is disruptive selection and what is an example?
when survival of two different phenotypes is favored, more than one snail shell color is preserved because different environments have different shell colors that are favored
what is stabilizing selection and what is an example?
when survival of individuals with intermediate phenotypes is favored, laying a medium amount of eggs is favored as opposed to laying too many to take care of or too few to survive
in the field of population genetics and evolutionary biology what does the term fitness refer to?
the ability to survive and reproduce
what is the Hardy-Weinburg equation and what does each variable represent?
p^2 + 2pq + q^2 = 1
2pq: frequency of heterozygous individuals (Gg)
p^2: frequency of homozygous dominant individuals (GG)
q^2: frequency of homozygous recessive individuals (gg)
used to determine the expected frequencies of the genotypes in a population if they are not changing
if a population is at Hardy-Weinburg equilibrium for a particular gene what does this mean?
the population is not evolving
what is genetic drift?
random changes in allele frequency as a result of chance events, therefore is a small group of animals establishes a new population away from the original group then the new one is likely to be different from the original one
what is gene flow?
when individuals migrate between populations with different allele frequencies, pollen from one flower being carried to a new population or animals mating with another population
what is nonrandom/assortative mating?
when individuals choose to mate with those of a specific phenotype as opposed to choosing randomly
what is the correlation coefficient and what is the value of its degrees of freedom?
correlation coefficient is the strength of the association between two variables, its degrees of freedom is n-2
what is variance and what is the value of its degrees of freedom?
variance is the statistic to evaluate variation in a population, its degrees of freedom is n-1
what is covariance and what is the value of its degrees of freedom?
covariance is the degree of variation between two variables within a group, its degree of freedom is n-1
what are quantitative traits?
quantitative: study of traits that can be determined numerically and categorized as anatomical, physiological, behavioral, and human diseases
what characteristics do quantitative traits usually have?
environmental influence, polygenic basis, and continuous distribution
what is heritability and how do you interpret its value?
heritability is a measure of whether observed variation is due to genetics or the environment
a heritability value of 1 means all of the variation is due to genetics
a heritability value of 0 means all the variation is due to the environment
how can you determine the total variance of a population for a quantitative trait?
sum the genetic and environmental variances
what does quantitative trait loci mapping determine?
determines relationships between quantitative traits and molecular markers such as RFLPs
what is a critical factor for preparing genomic DNA to make a library for genome sequencing?
partially digesting the DNA with a restriction enzyme
which technique is needed when performing an RFLP analysis to test for a genetic disease?
southern blot
why is Sanger sequencing no longer used for genome sequencing?
the products of a sequencing reaction need to be separated to determine the DNA sequence, it is relatively slow, and it is relatively expensive
what is used as “probes” to study protein expression in a protein microarray?
antibodies
how can you determine if genes are homologs?
if genes are orthologs (genes at the same locus) they will have the same number, if genes are paralogs (related genes within or between species) there will be a corresponding genes in the other species where it is blank for one species, orthologs and paralogs both count as homologous species
what are different types of BLAST searches and what are they used for?
blastn: nucleotide vs nucleotide (used for DNA to DNA research)
blastx: translated nucleotide vs protein database (used for DNA to cDNA research)
blastp: protein vs protein database (used for amino acid to protein research)
what is mapping?
the experimental process of determining the relative location of genes or other segments of DNA along individual chromosomes
what is replacing microarrays as a powerful tool to study gene expression?
transcriptome sequencing