Mendelian Genetics Flashcards
Pure Breeding Line
Same trait bred for generations
Reciprocal crosses
A pair of crosses between the male of one and the female of the other, and vice versa
Self-fertilization
Gametes come from same organism
Phenotype
Observable genetic trait
Genotype
The “genetic makeup”
Gametes
Reproductive cells
Monohybrid cross
Mating between individuals that differ by one trait
Allele
Single unit of inheritance
Polymorphic
A gene that has several alleles that normally occur in the population, more than one wild-type
Monomorphic
Only one allele that is normally present in the population, only one wild-type
Mendel’s Law of Segregation
Two alleles for each trait separate during gamete formation, the unit (one from each parent) is random at fertilization
What is the phenotype ratio for a heterozygous monohybrid (Aa x Aa) cross?
3:1
Incomplete dominance
Traits are blended into new phenotype
What is the genotypic ratio for incomplete dominance?
1:2:1
Codominance
When both traits are present
What is the phenotypic ratio for codominance
1:2:1
Wild-type allele
Greater than 1%
Mutant allele
Less than 1%
Pleiotropy
Multiple phenotypic effects caused by a single gene
What is the phenotypic ratio of heterozygous parents that can pass on recessive lethal alleles?
2:1
Multifactorial inheritance
A phenotype arising from the action of two or more genes (polygenic) or from interactions between between genes and the environment
Complementary gene action
Two or more genes working in tandem, in the same biochemical pathway to produce a particular trait
Complementation
Mutations from 2 different genes that result in same phenotype, off-spring is not affected by mutation
What is the phenotypic ratio for complementary gene action
9:7
