Mendelian Genetics

KEY VOCABULARY  Dominant: inherited characteristic that appears in an organism- usually represented with capital letter.  Recessive: inherited characteristics often masked by the dominant characteristic and not seen in an organism- usually represented with lowercase letter.

Dominant vs. Recessive Dominant- Widow’s Peak (W) Recessive- No Widow’s Peak (w)

Vocabulary Phenotype  physical traits that appear in an individual as a result of its genetic make-up –Ex:  Purple flower vs. White flower Genotype  Genetic Make Up of an individual –Ex:  P= purple; p= white  PP

Vocabulary  Allele: different forms of the gene for a trait (2 for each trait)

For Example:  # 4 from Mom# 4 from Dad Both have hair color information

For Example: But Mom’s could say “blonde” While Dad’s says “brown”

Vocabulary –Homozygous: having two identical alleles (PP or pp) –Heterozygous: having two different alleles for a trait (Pp)

Mendel’s Experiments Three Principles

Principle of Dominance  one trait is masked or covered up by another trait

Principle of Segregation the two factors (alleles) for a trait separate during gamete formation

Principle of Independent Assortment  factors of a trait separate independently of one another during gamete formation; –EX: whether a flower is purple has nothing to do with the length of the plants stems - each trait is independently inherited