Beyond Mendel's Laws

Flashcards reviewing key concepts related to the variations from Mendel's laws, gene expression, eye color genetics, lethal alleles, and concepts like incomplete dominance, codominance, penetrance, and pleiotropy.

What are the three general phenomena that seem to be exceptions to Mendel’s laws?

Gene expression, mitochondrial inheritance, and linkage.

What is a lethal allele?

A lethal genotype that causes death before the individual can reproduce.

What gene is controlled by OCA2 in relation to eye color?

OCA2 controls melanin synthesis which affects eye color.

What does incomplete dominance in genetics refer to?

The expression of a phenotype that is intermediate between those of the two homozygotes.

What is Codominance?

When both alleles in a heterozygous gene pair are fully expressed.

What is penetrance?

The probability that a phenotype will appear when the disease genotype is present.

What is an example of a condition affected by pleiotropy?

Marfan syndrome.

How does epistasis modify expected phenotypic ratios?

It occurs when the alleles of one gene mask the effects of alleles of another gene.

What is a compound heterozygote?

An individual with two different mutant recessive alleles for the same gene.

What is genetic heterogeneity?

Different genes can produce identical phenotypes.