Non Mendelian Genetics Flashcards
What is Non-Mendelian Genetics?
Many traits do not follow the ratios predicted by Mendel’s laws
This includes varying degrees of dominance, multiple genes acting together, and traits determined by genes on sex chromosomes.
What are the degrees of dominance?
Alleles can show varying degrees of dominance
This includes complete dominance, incomplete dominance, and codominance.
Define incomplete dominance.
Neither allele is fully dominant, resulting in a phenotype that is a mix of those of the parental generation
Example: red flowers crossed with white flowers produce pink offspring.
What is codominance?
Two alleles that affect phenotype are both expressed
Example: Type AB blood where both A and B alleles are expressed.
What are multiple alleles?
Genes that exist in forms with more than two alleles
Example: human blood group with alleles I_A, I_B, and i.
What is epistasis?
The phenotypic expression of a gene at one locus affects a gene at another locus
Example: coat color in labs and some mice.
What is polygenic inheritance?
The effect of two or more genes acting on a single phenotype
Example: height and human skin color.
What are sex-linked genes?
Genes located on either the X or the Y chromosome
X-linked genes are more common than Y-linked genes.
How do fathers and mothers pass X-linked alleles?
Fathers pass X-linked alleles to all daughters but none to sons; mothers can pass X-linked alleles to both daughters and sons.
What is hemizygous?
Males with only one X chromosome express X-linked traits if they inherit them from their mother
This term applies because heterozygous does not apply to males.
List examples of X-linked disorders.
- Duchenne muscular dystrophy
- Hemophilia
- Color blindness
Define genetic recombination.
Production of offspring with a new combination of genes from parents.
What are parental types and recombinants?
- Parental types: offspring with the parental phenotype
- Recombinants: offspring with phenotypes different from the parents.
What are linked genes?
Genes located near each other on the same chromosome that tend to be inherited together.
