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P= 0

impossible event

P= 1

certain event

Addition Rule

For mutually exclusive "OR" events, you add the probabilities

Multiplication Rule

For independent "AND" events multiply the probabilities

Allele

alternative forms of a particular gene that are present at a single locus.

Alelle Frequency

the proportion of a specific allele relative to all other alleles in a population

Genotype frequency

The proportion of a specific genotype relative to all other genotypes in a population

Phenotype frequency

The proportion of a specific phenotype relative to all other phenotypes in a population

p+q=1

For two alleles, present in a population, the relative frequencies are equal to 1

Hardy Weinberg Equilibrium Conditions

Random Mating, Infinitely large population, No mutation, No migration into or out of the population, No selection for either trait

Assortative Mating

like mating with like, where partners select each other based on a shared trait or characteristic

Consanguineous mating

matings between closely related individuals

Fixative Genes Can Lead to

Small Population Size

Random Genetic Drift

allele frequencies in a population change from one generation to the next due purely to chance

Founder effect

Specific alleles that are more rare, become not as rare

Bottleneck

deleterious alleles are amplified, when a population decreases then reproduces again

Dunker Blood type

example of Founder effect

Selection

Differences in reproductive or Genetic Fitness

Heterozygote advantage

Hemoglobin S allele confers resistance to malaria

CFTR

heterozygote resistant to diarrheal disease

HEXA

heterozygote resistant to tuberculosis

PAH

heterozygote resistant to abortion caused by fungus

Gene Flow

Migration, slow diffusion of alleles across a racial or geographical boundary

q^2

the freq. of homozygotes for the a allele

p^2

the freq. of homozygotes for the A allele

2pq

the freq. of heterozygotes

Disease Frequency= (for autosomal recessive)

q^2

Females allele frequency of X-linked genes; genotype frequency

p+q=1; p^2+2pq+q^2=1

Males genotype frequency for X-linked traits; allele frequency

p + q=1; p+q=1

Fitness

the measure of the number of offspring of affected persons who survive to reproductive age. Ranges from 0-1

Coefficient of Selection

1-f, or s

Autosomal dominant traits (mutations equation)

u= sq or u=(1-f)q

X-linked recessive if the phenotype is benign

u=sq/3 or u= (1-f)q/3

x-linked genetic lethality, where mutation causes a very deleterious phenotype

1/3 of all copies of mutant allele will be lost in each generation

Coefficient of relationship (def.)

a measure of the proportion of genes shared by two related individuals as a result of their genetic relationship

Coefficient of relationship (equation)

1/2^n

Coefficient of Inbreeding (def)

a masure of the probability that a person has received both alleles of a gene from a common ancestor

Coefficient of Inbreeding (equation)

1/2*1/2^n= 1/2^(n+1)

Mutually exclusive

either one outcome or the other will occur

Independent

when the probability of one event does NOT effect the probability of another event's occurrence

Prior probability

The initial probability of an event

Conditional probabilities

probabilities determined by observations or posterior information

Joint probability

probability resulting from multiplication of the prior probability with each appropriate conditional probability

Posterior Probability

Probability resulting from dividing the joint probability for each event, by the sum of the joint probabilities

Autosomal dominance risk for passing on mutant allele to offspring

1/2

Example of delayed onset disease

huntington's

Autosomal recessive risk for passing on mutant allele to offspring

1/4

Autosomal recessive risk for producing children that are heterozygous

2/3

For sex linked recessive traits, affected males...

daughters will all be carriers

Carrier mothers of sex-linked recessive traits

1/2 of sons will be affected