Chapter 16 Flashcards
Result of independent assortment
4 possible gametic types are produced in equal proportions
Principle of independent assortment
Segregation of one set of alleles of a gene pair is independent of the segregation of another set of alleles
Linked chromosomes
Do not assort independently
Epistasis
- Gene that modify the phenotypic expression of other genes
- 2 genes each w/ 2 alleles
Pedigree
Diagram of family history
Principle pedigree characteristics of dominant traits
- equally likely to be male or female
- most mating that produce affected offspring have one affected parent
- approx. 1/2 offspring affected
Principle pedigree characteristics of recessive traits
- May skip one or more generations
- equally likely to be male or female
- May have unaffected parents
- affected often through mating between relatives
- must be inherited from both parents
Multiple alleles
Many alleles of the same gene
Mutant alleles
DNA sequence different but none produce a functional protein product
Normal alleles
DNA sequences different but all produce functional protein product
Incomplete Dominance
Hybrid Phenotype
Codominance
Expression for both alleles is observed as distinct phenotype in heterozygous individual
Variable expressivity
- particular phenotype expressed with a different degree of severity in different individuals
- trait always expressed
Genetic tests
- method of identifying genotype
- identify genetic risk factors for disease
Mendels reason for using pea plants
- cheap
- easy to grow
- short generation time
