Topic 2 Flashcards
what is the gametic ratio of a dihybrid cross with independent assortment?
1:1:1:1
What is the phenotypic ratio of a dihybrid cross with independent assortment?
9:3:3:1
what is the phenotypic ratio of a dihybrid test cross with independent assortment?
1:1:1:1
how to calculate the number of gamete types for crosses with multiple genes
2^n (n=num of gene pairs)
how do you calculate number of possible genotypes in crosses?
3^n (n=num of gene pairs)
how many possible genotypes exist in a trihybrid cross
3^3 (3 gene pairs) = 27
what does unlinked genes mean?
genes that are on different chromosomes
what does linked genes mean
genes on different loci of the same chromosome
how many types of gametes would you get in a dihybrid cross unlinked?
4 (2^n 2^2 2 genes)
how many types of gametes would you get in a trihybrid cross unlinked?
8 (2^n 2^3 3 genes)
what is the gametic ratio of a test cross with a dihybrid F1
1:1:1:1
what is the ratio for independent assortment in a dihybrid meiocite
1:1:1:1
how many genotypes are produced with 2 gene pairs?
3^2 = 9
how many genotypes are produced with 3 gene pairs?
3^3
what is the assumption for testing for whether it is linked or unlinked genes
the assumption is that it is undergoing independent assortment and that the phenotypic ratio is 9:3:3:1
how do you calculate degrees of freedom for linkage
num of phenotypes - 1
what accounts for Mendel’s first law in meiosis
Segregation of a pair
of homologs by spindle attachment from each pole
what accounts for Mendel’s second law in meiosis
The randomness of spindle attachment
throughout the chromosome
what is a dihybrid cross
a cross between individiuals that differ with respect for 2 traits (heterozygous for 2 traits)
what accounts for mendels second law (law of independent assortment)
in metaphase I, homologous pairs line up at metaphase plate indepenently from others
