1. Chp. 10
GENETICS

2. GENETICS The study of heredity
Traits- characteristics that are inherited
Heredity- passing on of characteristics from parent to offspring

3. ALLELE Gene form for each variation of a trait of an organism
One allele is inherited from the female (mom) & the other from the male (dad)

4. DOMINANT GENE Visible, observable trait of an organism
Masks the recessive form of the trait
Represented by a capital letter (T, S)

5. RECESSIVE GENE Hidden trait of an organism Masked by the dominant gene
Represented by a lower case letter
(t, s)

6. PHENOTYPE The way an organism looks Physical appearance
Ex: tall, short, blonde hair, brown eyes

7. GENOTYPE The gene combination of an organism
Two letters representing the genes
Ex: TT, Ss, ss

8. HOMOZYGOUS/PURE
The 2 alleles for the trait are the same
Ex: TT, SS, tt, ss
Homozygous recessive- the two alleles are recessive. Ex: tt, ss
Homozygous dominant- two alleles are dominant. Ex: TT, SS

9. HETEROZYGOUS/HYBRID The two alleles for the trait are different
A capital letter and a lower case letter
Ex: Tt, Ss
Also known as HYBRID!

10. LAW OF SEGREGATION
The two alleles for each trait separate during meiosis
During fertilization, the two alleles for that trait unite

11. LAW OF INDEPENDENT ASSORTMENT
A random distribution of alleles occurs during gamete formation
Genes on separate chromosomes sort independently during meiosis
Ex. Plant height & flower color

13. INHERITANCE OF TRAITS P Generation- parents
F1- first filial generation, offspring of parents
F2- second filial generation, offspring of F1

14. PUNNETT SQUARES
Monohybrid cross- results is a 3:1 phenotypic ratio of dominant to recessive.
Uses one trait (height)
A true monohybrid cross involves two heterozygous individuals

15. DIHYBRID CROSSES Cross involving two different traits
Ex: round yellow seeds vs. wrinkled green seeds
The alleles combine in four different ways
A true dihybrid cross involves two individuals that are heterozygous for both traits
Results in a 9:3:3:1 phenotypic ratio