AP bio Unit 5 Flashcards
Complete dominance
1 allele shows a trait while one does not
Co-dominance
All alleles expressed (eg: blood type)
Incomplete dominance
3 phenotypes controlled by 2 alleles (eg: Red, pink, white flowers)
multiple alleles
1 trait expressed, 2 alleles inherited, but more options for alleles
pleiotropy
1 gene affects multiple traits
epistasis
One gene’s expression depends on the expression of another gene (eg. lab dogs)
chi-square use
Analyze the inheritance patterns of linked genes
monohybrid cross
One trait
Phenotypic ratio in monohybrid cross
3:1
Linked genes
same chromosome
Phenotypic ratio in a dihybrid cross
9:3:3:1
purpose of using a chi-square test in genetic studies
To test the goodness of fit between observed and expected results.
In a monohybrid cross between two heterozygous parents (Aa x Aa), what percentage of offspring will be homozygous recessive?
25%
Chi square formula
χ² = Σ((O - E)² / E)
Chi-square value meaning
Greater = significant difference, less= consistent with null hypothesis
In a dihybrid cross involving two heterozygous parents (AaBb x AaBb), how many different genotypes can be produced?
9
Crossing over in linked genes
It can create new allele combinations, reducing the degree of linkage.
genotypic ratio of offspring in a monohybrid cross
1:2:1
P meaning
Parental generation
Expected ratio of phenotypes in a dihybrid cross of heterozygotes (not linked)
9:3:3:1
test cross
A cross between an individual with an unknown genotype and a homozygous recessive individual.
F1 meaning
First filial generation
Recombinants
Made by combining genetic material from two sources
Sex linked traits
traits on the X or Y chromosome that generally manifest in different proportions in men and women
