Population Genetics Flashcards
difference between chromosome gene and allele
chromosomes are structural units of genetic material then the genes are the units of heredity located on chromosomes then the alleles are the versions of a gene
what is the monohybrid test cross
determine if an individual exhibiting a dominant trait is homozygous or heterozygous
gross the unknown genotype with a homozygous recessive
difference between incomplete dominance and co-dominance
incomplete - dominant doesnt completely mask the effects of the recessive, shows intermediate phenotype
co - the heterozygote fully expresses the phenotype of both alleles
describe results of a dihybrid cross (genes for 2 separate characteristics
if both heterozygous for both traits
9:3:3:1
what dihybrid cross would produce a ratio of 1:1:1:1
heterozygous F2 (SsBb) x homozygous recessive (ssbb)
what is mendels law of independent segregation
alleles separate independently of each other when forming gametes (meiosis 1)
gamete will only get 1 allele, a zygote will get 2
what is mendels law of independent assortment
alleles of genes on different chromosomes assort independently during gamete formation
in metaphase 1 of meiosis homologous chromosomes align independently
If genes are located on the same chromosome what is the likelihood that they will remain together during crossover in prophase 1 related to
Indirectly proportional to the distance separating them
Far apart - small chance of staying together
If genes are located on the same chromosome and the question states that the genes were link what would that mean
If A1B1 genes are linked on the same chromosome then their gametes would be A1B1
What’s the difference between single or double cross over in prophase 1
Single has less recombination variation
Mitochondria and mtDNA are inherited from the mother make it what type of lineage
Single so it can be traced back
crossing over in prophase 1 provides genetic recombination, the likelihood genes on the same chromosome remain together is indirectly proportional to
the distance separating them
far apart = small chance of staying together
mitochondria and mtDNA are inherited from the mother only making it what kind of lineage
single
what is a Barr body
in somatic cells one X chromosome remains inactivated
what is penetrance
probability of a gene or allele being expressed if it is present
what is expressivity
degree to which a particular phenotype expresses itself in the genotype
what is the order of taxonomical classification
dumb kids playing cards on freeways get smashed domain kingdom class order family genus species
what is a gene pool
total collection of alleles for all the loci in a population
which conditions must be meant for there to be no change in the gene pool of a sexually reproducing population according to hardy weinberg
large population mutational equilibrium no change from immigration or emigration random mating no selection for the fittest organism
how can you predict the genotype frequency of a gene with only 2 alleles in a population that exists in hardy Weinberg equilibrium *** will be on exam
p^2 + 2pq + q^2
where p+q=1
where p and q are the frequencies of a gene in a population
define species
group of organisms capable of interbreeding and producing fertile offspring
what is speciation
single ancestral species splits into multiple new species or a single species evolves into a reproductively distinct new species
what are the two types of genetic drift
bottleneck effect: a population contracts to a significantly smaller size over a short period of time due to a random environmental event thereby leading to a loss of alleles
founder effect: small group of individuals leaves to establish a new population which their gene pool will reflect the alleles carried by the founders
what is gene flow
transfer of alleles of genes from one population to another
what is the result of inbreeding
frequency of homozygotes increases while heterozygotes decreases
genetic diversity decreases
what is the result of outbreeding
increases heterozygosity
what is the difference between evolution and natural selection ***
evolution is the change in the inherited traits of a population of organisms over time and natural selection is a mechanism for this. natural selection is considered survival of the fittest
what is a niche
all of the biotic and abiotic factors required by an organism
what is carrying capacity
max population size of a species that can be sustained indefinitely by the environment
what are some qualities of r selected species (r think rabbits )
put more energy into reproduction than parental care
present in unstable or unpredictable environments
often small body size and early maturity onset
what are some qualities of k related species (k think kids )
put energy into ensuring offspring survive
found in stable environments often close to the max the environment can bear so must be able to compete for limited resources
large body size
long life expectancy
production of fewer offspring
define karyotype
number of chromosomes in the nucleus of a eukaryotic cell
define mendelian error
allele in an individual which could not have been received from either of its biological parents by mendelian inheritance
define leakage
gene flow from one species to another
define adaptive radiation
evolution of ecological and phenotypic diversity in a lineage that allows them to exploit a range of divergent environments
define divergent evolution
2 or more species evolving from the same group maintain a similar structure from eh common ancestor
ex. Darwins finches
what is convergent evolution
two species evolve similar traits with no recent common ancestor
ex. bats and birds have wings
define polymorphism
2 or more different phenotypes exist in the same population of species
define mutualism
interaction between 2 species where each individual derives a fitness benefit
ex. bees pollinate flowers
define commensalism
relationship where one organism benefits and the other is unaffected
define genetic drift
change in allelic frequency of a population due to random sampling caused by bottleneck or founder effect
