Genetics Flashcards
Mono hybrid cross
Cross a homozygous recessive with a homozygous dominant
What is the P generation, the F?
P is parent which are the individuals being crossed and F are the offspring
What will the first generation of a mono hybrid cross be
All heterozygous
What is the result of a self cross of two F1
25% PP, 50% Pp, and 25% pp. This is phenotypically a 3:1 ratio
What is a test cross
Looking at the offspring to try and figure out the genotype of the parents
In a dihybrid cross what are the results of the F1 and F2 generations
F1 is all heterozygous
F2 is 9:3:3:1 as a phenotypic ratio
In a dihybrid cross what do you cross
Homozygous recessive for two traits with homozygous dominant for two traits
When you cross a heterozygous dominant trait with a homozygous recessive one what is the approximate ratio of phenotypes in offspring
1:1
When you cross a heterozygous with a heterozygous what is the approximate ratio of phenotype offspring
3:1
What is the phenotypic ratio when you cross a heterozygous dominant trait with a homozygous recessive
1:1
What is the phenotypic ratio when you cross two heterozygous
3:1
Frequency of recombination can range from
0 to 50, 50 being completely unlinked
What would happen if there was crossing over between sister chromatids
Nothing, thy are identical
When does crossing over occur
Prophase 1
One map unit corresponds to
A 1% chance of recombination occurring
What happens to the F2 generation in incomplete dominance
1 red 2 pink 1 white vs the 3:1 phenotypic ratio
Blood alleles Ia and Ib are
Codominant to O
Penetrance
Number carrying allele who actually express the phenotype
Expressivity
Various expression of disease symptoms despite identical genotypes
Sex is determined by
Father
If a male carries a mutation X they will be affected. This is called
Hemizygous
What will the children of a male infected with a y linked disease e
Sons will all be affected no daughters will be
What will the phenotype be if there is a carrier female and a normal male
50% of sons will have it, none will be carriers. Overall distribution is 25%
If the mother is a carrier ad the dad has it
50% of daughters are hemopheliacs, 50% will be carriers. 50% of males will have it, 50% of make will be normal
What is it called when someone has a variation of the 46 chromosomes
Aneuploid, most commonly disjunction
XXX
Metafemales
XXY
Klinefelter male
Translocation
One chromosome adds to another
Inversion
Inserts itself in opposite inversion
