OPEN YELLOW BOOK TO PAGE 176-177 Copy the vocab

Genetics Study of heredity

Heredity Passing of traits from parents to offspring

Gene Sections of DNA on a chromosome that carry info/genetic instructions about a certain trait

Trait Inherited characteristics about an organism Examples: hair color, blood type

allele Different forms of the same gene for a particular trait

Dominant A gene that controls its recessive form The expressed for of a trait Controls the phenotype Represented by a capital letter

Recessive Gene that can be controlled by a dominant form Covered up/masked by dominant trait Only expressed when both genes in a pair are recessive Represented by a lower case letter

Homozygous Paired traits(alleles) for a gene are the same Examples: RR

Heterozygous Paired traits(alleles) for a gene are different HYBRID – 1 dominant and 1 recessive Example: Rr

genotype The gene makeup/combination for a trait Determines the phenotype Examples: RR Rr rr

phenotype Physical appearance of a trait The trait the organism shows Determined by the genotype Examples: Tall or short Blue eyes or Brown eyes

Gregor Mendel Father of genetics 1st to discover how offspring inherited traits from their parents using pea plants Discoveries One gene from mother and one from father for the same trait Dominant and Recessive Homozygous and Heterozygous

Punnett Square Chart used to display the potentional/possible genotypes of offspring from a particular male and female parent

Law of Segregation Due to meiosis, each gamete that is made only receives 1 copy of each gene

Law of Independent Assortment Alleles of different genes sort independently of each other during meiosis

Law of Dominance If an organism is heterozygous, only the dominant trait will be seen and recessive will be hidden

Incomplete Dominance Inheritance in which 2 different genes combine to form a blended phenotype Both traits expressed to a degree Example: Snapdragons RR crossed with rr Yields: Rr  pink color expressed