Chromosomes and Inheritance - Ch. 9 Flashcards
What’s an allele? What’s a genotype? Phenotype?
Alleles are different forms of a given gene.
Genotype– the gene forms of any given organism, e.g. HhRr
Phenotype– expression of a gene, e.g. color
What kind of Punnett Square do you use in a dihybrid cross?
16-Square
Heterozygous
Carry DIFFERENT alleles.
Example: Pp
Homozygous
Carry the SAME allele on both chromosomes
Example: PP (homozygous dominant) and pp (homozygous recessive)
What is Mendel’s Law of Independent Assortment?
Mendel’s law of independent assortment states that allele pairs separate independently during the formation of gametes.
What is Mendel’s Law of Segregation?
Mendel’s Law of Segregation states that allele pairs separate during gamete formation, and randomly unite at fertilization.
Testcross
breeding an organism of unknown genotype with a recessive homozygote; determines the genotype of parent with dominant phenotype
What organism did Mendel work with to study inheritance?
garden peas
Complete dominance
the effect of one allele in a heterozygous genotype completely masks/dominates the effect of the other
Incomplete dominance
phenotype of heterozygote is an intermediate between the phenotypes of the 2 homozygous
example: RR = red, rr = white, Rr = pink (a blend on the 2 colors)
Codominance
the 2 alleles/genes an individual has both affect the phenotype in separate and distinguishing ways
What is the Rule of Multiplication?
compound event is the product of separate events
What is an example of a gene with multiple alleles?
Human blood groups (ABO)
What are sex-linked traits? What’s an example of a sex-linked trait?
Genes that are carried by either sex chromosome (X, Y) are said to be sex linked. Most sex-linked genes are located on the X chromosome. An example of a sex-linked trait is red-green color blindness.
What kind of Punnett Square do you use in a monohybrid cross?
4-Square
