Mendelian Genetics (Laws of heredity) Flashcards
Phenotype
Physical appearance of a trait formed by genetics on environment.
Parental generation (P)
The purebred line without crossbreeding
Filial generation (Fn)
A generation from the parental generation. The number noted how many generations away from the parents a specimen is i.e. F2 is 2 generations away (the parent generation is the grandparent
What ratio do dominant and recessive phenotypes present in F2 generations?
3:1
Allele
A variant of a gene
Homozygous
The state of carrying a pair of identical alleles of a gene
Heterozygous
The state of carrying a pair of different alleles of a gene
Punnett Square
Used to predict the probability of a phenome in offstring
Mendel’s FIRST Law of Inheritance: the law of equal segregation
The equal distribution of alleles among gametes
Monohybrid cross
Looks at how a single trait is inherited when 2 heterozygotes mate
Dihybrid cross
Looks at how 2 genes fro single trait are inherited when 2 heterozygotes mate
Mendel’s SECOND Law of Inheritance: the law of independant assortment
When 2 or more characteristics are inherited, individual hereditary factors assort independently during gamete production giving different traits an equal opportunity of coming together.
Incomplete dominence
A heterozygote displays a phenotype that is blended with the two homozygous parent’s traits. white + red = pink
Codominance
A heterozygote displays a phenotype that shows both the homozygous parent’s traits. white + red = red + white spots
Epistasis
When a “modifier” gene influences the outcome of a different independent gene
In a dihybrid cross, how often does the dominant phenotype appear?
9/16 times
What are the blood type alleles and what shows codominance?
A, B, and O (i). AB shows codominance
What is the dihybrid F2 ratio?
9:3:3:1
What is the ratio for single F2 gene?
3:1
