| A | B |
|---|
| homozygous | two alleles are the same |
| heterozygous (hybrid) | two alleles are different |
| Law of Dominance | Mendel's law which states that when an individual is heterozygous for a trait, the dominant one is expressed. |
| Segregation | In gametogenesis the alleles one trait of the parents separate into different gametes since the homologous chromasomes separate. |
| Recombination | The separated alleles can come together in a new way when the sperm and egg come together in fertilization. |
| How does sexual reproduction create diversity in the population? | Alleles are separated and recombine causing new varieties of traits. |
| Dominant | The allele which is expressed |
| Recessive | The allele which is not expressed |
| homozygous recessive | rr |
| homozygous dominant | RR |
| heterozygous | Rr |
| Monohybrid cross | a hybrid crossing with a hybrid (Rr*Rr) |
| Gregor Mendel | the Father of Genetics |
| Gene-Chromasome Theory | States that traits are controlled by genes which are found in specific places on chromasomes |
| allele | pairs of genes on homologous chromasomes that control the same trait, but may be different "choices" for that trait (blue or brown eye color) |
| phenotype | what you look like |
| genotype | what your genes say you are |
| test cross | a way to determine if a dominant phenotype is heterozygous or homozyogous genotype (cross with a homozygous recessive) |
| Intermediate Inheritance | when the heterozygous phenotype is a mix between the homozygous phenotypes |
| Codominant | a type of intermediate inheritance where both alleles are expressed (roan cattle) |
| Incomplete dominance | a type of intermediate inheritance where the heterozygous is a blend between both alleles (pink flowers) |
| Independent assortment | most genes separate randomly in meiosis so two different traits are inherited independently (you might get hair color of mom, but eye color of dad) |
| Gene Linkage | sometimes genes do not assort randomly if they are found on the same chromasome (red hair and freckles) |
| How do we get variation if genes are linked? | crossing over |
| multiple alleles | some traits have more than two alleles even though only two alleles are expressed in any one person |
| sex determination | how sex chromasomes combine to make a male or female |
| XX | female |
| XY | male |
| autosomes | the 22 chromasomes controlling most "body traits" |
| sex chromasomes | the x and y chromasomes controlling sex determination |
| Thomas Hunt Morgan | used fruit flies to demonstrate that some genes are on the sex chromasomes |
| Sex-linked traits | genes which are located on the sex chromasomes and have a special inheritance pattern |
| carriers | females which carry a sex-linked gene, but do not have the trait since they are heterozygous |
