All Flashcards
What are the differences between genotype and phenotype?
Genotype: Genetic makeup (alleles) | Phenotype: Physical appearance of a trait.
What is the key difference in inheritance patterns between autosomal and sex-linked traits?
Autosomal: Affects males and females equally. Sex-linked: Different inheritance patterns in males and females due to X and Y chromosomes.
What is the definition of phenotype?
The physical appearance of a trait.
What is the definition of genotype?
The genetic makeup of a trait (the specific alleles).
What is an allele?
A version of a gene (dominant or recessive).
What does homozygous recessive mean?
Two recessive alleles (e.g., aa). Only this genotype shows the recessive phenotype.
Define a dominant allele.
An allele that masks the expression of a recessive allele (e.g., A).
Define a recessive allele.
An allele that is masked by a dominant allele (e.g., a).
What does homozygous dominant mean?
Two dominant alleles (e.g., AA). Shows the dominant phenotype.
What does heterozygous mean?
One dominant and one recessive allele (e.g., Aa). Shows the dominant phenotype.
What is a carrier in the context of sex-linked traits?
A female with one copy of a recessive X-linked allele; she doesn't express the trait but can pass it on.
What is the effect of having a homozygous recessive genotype?
The recessive phenotype is expressed.
Why are males more likely to be affected by X-linked recessive traits?
Males only have one X chromosome.
What is the typical phenotypic ratio in a dihybrid cross between two heterozygotes?
9:3:3:1