Dragon & Punnett Square Lab

Definitions:
1. Genotype: Genes of an individual for a particular trait or traits; often designated by letters. (BB or Aa, etc.) For example, the genotype of the two flies that are expected to produce 50% homozygous gray-bodied offspring and 50% heterozygous gray-bodied offspring must be GG for homozygous, and Gg for heterozygous grey-bodied offspring.
2. Phenotype: Visible expression of a genotype. For example, brown eyes, or the blue wings of my dragon. :)
3. Allele: Alternative form of a gene. Alleles control traits. A dominant allele is given an uppercase letter, while a recessive is given a lowercase. For example, the allele for my dragon's horns is Hh. Because there is a dominant H, my dragon has horns. If his allele for horns was hh, it would be recessive, and he would not have horns.
4. Cross: A method of determining whether or not someone with a certain genotype will have a certain phenotype. For example, a cross for two parents trying to determine if their children will have freckles would examine the alleles each parent has for freckles. If a homozygous dominant man with freckles (Ff) has a child with a woman who does not have freckles (ff), the child has a 3:1 chance of having them, too. This is because the possible resulting genotypes are FF, Ff, Ff, and ff. Only one of these combinations is recessive (ff), and would not have freckles. For the flies in the punnett square lab, parents were GG (homozygous dominant) and Gg (heterozygous dominant.) Because both were dominant, the offspring would all "inherit" a dominant G, and would therefore all be gray-bodied, not black.
5. Dominant allele: Allele that exerts its phenotypic effect in the heterozygote; it masks the expression of the recessive allele. In other words, in a genotype with a dominant allele, that dominant allele will "overpower" the recessive allele. Example: again, my dragon has horns with the genotype Hh, because the dominant allele H overtakes the recessive h.
6. Recessive allele: Allele that exerts its phenotypic effect only in the homozygote; its expression is masked by the dominant allele. So, if the recessive allele is paired with a dominant, the dominant allele is "taken" by the offspring. If, however, the allele is recessive, that is the allele that is passed on. Example, my dragon does not have scales because his genotype for scales is recessive: ss.

The punnett square was also fun. It was an interesting way to look at the same information, while being allowed to manipulate it hands on.

I thought this Dragon lab was really interesting. It was fun, manipulating his chromosomes and watching how he changed. By manipulating his alleles, I was able to create drastic changes in his appearance. Obviously, this shows that the changes made in chromosomes change the organism completely. In other words, by changing someone's genotype, we also change his or her phenotype.