Word list 8
1. Genotype- the genetic code of an organism, usually expressed with two letters, one letter from Mom’s side and one letter from Dad’s side. ( BB or Bb would represent the genotype of a person with Brown hair or Brown eyes)
2. Phenotype- a physical trait that is the result of a person’s genotype, brown hair is the phenotype of a person who’s genotype is “Bb”.
3. Homozygous- when a person receives the same gene or allele from both parents (BB or bb).
4. Heterozygous- when a person receives two different genes or alleles, a different one from each parent. (Bb)
5. Zygote- the first 2N cell that is created from the union of the egg (1N) and the sperm(1N).
6. Dominant alleles- alleles that take over in a person, they are the stronger genes, they will show up physically even if another allele (recessive allele) is present in the genotype.
7. Recessive alleles- alleles that are present in a person but that don’t show up if a person also has a dominant allele for the same trait. Recessive alleles will only show up in a person if they receive the recessive allele from both parents – they must be homozygous (bb) recessive to have the trait show up in the person physically.
8. Co- dominant alleles- alleles that don’t have a winner- both traits show up a little bit, think about a spotted animal – like a brown and white cow or a black and white cat.
9. Incomplete dominance- when alleles don’t have a winner so they meet in the middle, think about a black cat and white cat making a grey cat, or red and white making pink!
10. Polygenic – when more than one gene contributes to trait in an individual. Skin color is a result of 7 different genes, that’s why there is so much variation- any girl who ever had to buy foundation can relate to this!
