Inheritance patterns Flashcards
What is needed for a complete Punnet Square?
Parental phenotype and genotypes, gametes, F1 generation phenotypes ratio and a key
What does dihybrid mean?
Two characteristics present in the cross
Example of what dihybrid genotype?
RrYy x RrYy
What does codominance mean?
Both alleles are expressed
Examples of codominance?
Red, white, pink flowers and blood groups
Different alleles for blood groups?
A = IAIo or IAIA
B = IBIo or IBIB
AB = IAIB
O = IoIo
Ratio for a dihybrid cross?
9:3:3:1
What is Chi-squared used to see?
If the number of observed phenotypes (O) is significantly different to the number of expected phenotypes (E)
What is the Null Hypothesis for Chi-Squared?
There is no significant difference between the observed and expected
When do you accept the Null Hypothesis?
If Chi-Squared value calculated is lower than the P-value
What is autosomal linkage?
2 or more genes located on the same chromosome, typically inherited together
What is the recombinant of alleles?
Different forms of a gene that occupy the same position in a chromosome
What causes recombinant alleles?
Chiasmata and crossing over
If the genes are further apart is recombinant more or less likely?
More likely
Equation for recombinant frequency?
Number of recombinant offspring divided by the total number of offspring
If the percentage of recombinant alleles is above 50% what does that mean?
The genes are all on different chromosomes, the closer the genes the smaller the frequency
What is epistasis?
Interaction between gene loci, when the alleles mask other loci from presenting
Ratio for dominant epistasis?
9:7
Explain how dominant epistasis works?
If one dominant allele is present it is white, if both present then its purple (CCpp and ccPP = white, CcPp = Purple)
Ratio for recessive epistasis?
9:3:4
Explain how recessive epistasis works?
If 2 dominant alleles present then black, if only B dominant then its white, if only C dominant then its brown (BBCC, BbCc = Black, BBcc = White, bbCC = Brown)
