Inheritance Flashcards
State three causes of genetic variation
Mutation
Crossing over
Independent segregation
Random fusion of gamates
What is meant by a genome
All genes in a cell
What is a gene pool
All alleles in a population
How do multiple alleles of gene arises
Mutation
At different position in the gene
In genetic crosses the observed phenotypic ratios obtained in the offspring are often not the same as the expected ratios. Why
Small sample size
Fusion of gamete’s is random
Crossing over
Epistasis
Lethal genotypes
What is meant by a recessive allele
Only expressed in a homozygote
What does the hardy Weinberg equation predict
The frequency of alleles will stay constant from one generation to the next providing there are no mutations, selection or migration
Define gene linkage
Genes on same chromosome
Define epistasis
The allele of one gene affects expression of another phenotype
Describe why the observed phenotypes don’t match the expected values
Fusion of gamates is random
Small sample
Lethal alleles
Define codominance
Both alleles expressed in the phenotype
Rules for dominant alleles
Affected offspring must have at least one affected parent
Unaffected parents only have unaffected offspring
If both parents are affected and have unaffected offspring parents must be heterozygous
Male offspring are more likely than females to show recessive sex linked characteristics why
Makes only have one allele whereas females need two recessive alleles
Expected offspring phenotype ratio from heterozygous parents for monohybrid
3:1
Expected offspring phenotype ratio from heterozygous parents for dihybrid
09:3:3:1
