IN 147 Headings Vocabulary Important Info Genetic Variation IN 147 Headings Vocabulary Important Info

The Law of Segregation Mendel’s 1st Law The 2 alleles of each gene pair separate into different gametes (egg or sperm) during meiosis.

The Law of Independent Assortment Mendel’s 2nd Law Independent Assortment: Genes that are inherited separately… Do NOT influence the inheritance of others Alleles segregate independently during meiosis Some ALLELES go to one gamete and some to another

INCOMPLETE DOMINANCE Incompletely dominance: Genes are neither dominant nor recessive= they mix!!! Genotype is heterozygous (hybrid--Hh) Phenotype is between two parents Dominant gene cannot fully mask the recessive Ex: white flower x red flower = pink flowers

CODOMINANCE Codominance: Offspring shows phenotype of neither parent Both alleles are DOMINANT!!! Ex: black chicken x white chicken = checkered chicken

MULTIPLE ALLELES Multiple alleles: Two OR More alleles control a trait You still will only have two of these alleles.  Ex: height, hair color, eye color and blood type   There are 3 different alleles for blood:  (Type A) = IA IA or IA i (Type B) = IB IB or IB i (Type AB) = IA IB (Type O) = ii

Sex-Linked Alleles Sex-linked alleles: controlled by genes located on sex chromosomes (XX or XY) Usually carried on X chromosome Since females are XX, they are usually carriers of the trait Since males are XY, they have a higher tendency for inheritance of trait

If trait is X-linked, MALES: pass it to all daughters none to sons If trait is X-linked, MOTHERS: have 50/50 chance of passing it to all of their children Ex: colorblindness, hemophilia, male pattern baldness