Lecture 2 Flashcards
(22 cards)
test cross
used to find the genotype of an individual
testor
the individual that has a homozygous recessive genotype for the trait in question.
How to find the unknown genotype
cross the individual with the testor
backcross
the F1 individual is crossed to one of the parental genotypes (can also be a test cross)
Punnet square
most useful for monohybrid cross
multiplication rule
the probability of 2 or more independent events occurring together is the product of their probabilities.
look for “and”
addition rule
the probability of any one of two or more mutually excuslive events is the sum of their probabilities
look for “or”
wild type
the common allele for a character, the allele usually found in the wild. designated with a (+)
dihybrid cross
parents differ in two characteristics
Mendel’s principle of independent assortment
alleles at different loci separate independently of one another
- extension of principle of segregation
Phenotypes of F2 progeny
9:3:3:1
dihybrid cross is really
just two monohybrid crosses when the genes at the two loci assort independently
R_
RR or Rr. either allele is possible
goodness of fit chi-square test
to evaluate the role of chance in producing deviations between observed and expected values
- the probability that the difference between observed and expected values is due to chance
chi square value
x^2 = sum of ((O-E)^2)/E
degrees of freedom
n-1 where n is the number of expected phenotypes
significance value we use
5% significance
stating your hypothesis
The mode of inheritance for ________(trait) in _______(organism) is __________(type of inheritance)
chi squared value less than table critical value
fail to reject your hypothesis
less than table value conclusion
The data for ______(trait) in _________ (organism) are consistent with _________ inheritance at the 5% significance level
chi squared value greater than table critical value
reject your hypothesis
reject hypothesis conclusion
The data for _______(trait) in __________(organism) are significantly different from __________ (type of inheritance) at the 5% significance level.
