Lab 8: Dihybrid Crosses, Sex-linked Inheritance, and Human Genetics

Vocabulary flashcards covering genetic terminology, Mendelian inheritance laws, and non-Mendelian extensions from the Lab 8 lecture notes.

Genotype

The genetic make up or your DNA code.

Phenotype

The physical expression of a genotype, which can depend on the environment and the interaction between genotype and environment.

Alleles

Versions of the same gene.

Homozygous

Having two alleles that are the same, represented as $AA$ or $aa$.

Heterozygous

Having two alleles that are different, represented as $Aa$.

Dominant

An allele trait that only needs one copy to be expressed, such as in $Aa$ or $AA$ genotypes.

Recessive

An allele trait that needs both copies to be expressed, represented as $aa$.

Independent Assortment

A process during gamete formation (meiosis) where different alleles for traits assort independently and randomly of each other.

Punnett Square

A tool used to visualize the probable genotype and phenotype frequencies of offspring by combining parent gametes.

Dihybrid Punnett Square

A Punnett square used to test the probability of passing on two traits simultaneously, related to the Law of Independent Assortment.

Sex Linked Inheritance

Inheritance resulting in unique patterns according to the gender of the offspring, involving traits on sex chromosomes ($XX$ for females, $XY$ for males).

Hemophilia

A sex-linked recessive disease referred to as "The Royal Disease," where $H$ is normal and $h$ is the recessive hemophilia allele.

Incomplete Dominance

A genetic extension where heterozygotes have an appearance that is intermediate between homozygotes, such as pink flowers resulting from red and white parents.

Polygenic Inheritance

The additive effect of many genes on one phenotype, recognizable by continuous variation, such as height, weight, eye color, and skin color.

Zea Mays

The scientific name for corn, used in dihybrid cross investigations to examine the inheritance of two traits.

Continuous Variation

A range of phenotypes recognizable in polygenic inheritance examples like intelligence or skin color.

X chromosome

The sex chromosome where traits like Color Blindness, Hemophilia, and Muscular Dystrophy are usually located.

Y chromosome

The sex chromosome present only in males ($XY$).