D3.2

2. a recessive genetic disorder involving the inability to metabolize a specific amino acid.
3. A sex-linked genetic disorder where the blood does not clot properly.
4. Testing a suspected heterozygote by crossing it with a known homozygous recessive individual.
5. The observable physical characteristics or traits of an organism.
7. The first filial generation; the offspring resulting from a cross between two parent organisms.
9. The particular position on a homologous chromosome where a gene is located.
12. An allele that has the same effect on the phenotype whether it is paired with the same or different allele.
14. Any chromosome that is not a sex chromosome.
15. When a single characteristic is controlled by the alleles of two or more genes.
17. A pattern where the heterozygote has an intermediate phenotype between the two homozygotes.
18. Having two different alleles of a gene.
20. The amino acid that cannot be produced from phenylalanine in individuals with PKU.
21. A chart showing the inheritance of a trait through several generations of a family.

1. An allele that only has an effect on the phenotype when present in the homozygous state.
2. The ability of one genotype to produce different phenotypes in different environments.
6. A grid used to predict the possible genotypes and phenotypes of offspring.
8. An individual that has one copy of a recessive allele that causes a genetic disease in individuals that are homozygous.
10. Alleles that both affect the phenotype when present in a heterozygote, such as in AB blood groups.
11. Having two identical alleles of a gene.
13. A range of phenotypes for a trait that cannot be placed into discrete categories.
16. The symbolic representation of the pair of alleles possessed by an organism.
19. Patterns of inheritance where the gene is located on the X or Y chromosome.