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What is incomplete penetrance and what causes it?

What is gene interaction? What is the difference between an epistatic gene and a hypostatic gene?

What is a recessive epistatic gene?

What characteristics are exhibited by a cytoplasmically inherited trait?

What is genomic imprinting?

What is the difference between genetic maternal effect and genomic imprinting?

What is the difference between a sex-influenced gene and a gene that exhibits genomic imprinting?

Match each of the following terms with its correct definition (parts \(a\) through \(i\) ). \- Phenocopy \- Pleiotropy Polygenic trait Penetrance Sex-limited trait \- Genetic maternal effect \- Genomic imprinting Sex-influenced trait Anticipation a. The percentage of individuals with a particular genotype that express the expected phenotype. b. A trait determined by an autosomal gene that is more easily expressed in one sex. c. A trait determined by an autosomal gene that is expressed in only one sex. d. A trait that is determined by an environmental effect and has the same phenotype as a genetically determined trait. e. A trait determined by genes at many loci. f. The expression of a trait is affected by the sex of the parent that transmits the gene to the offspring. g. The trait appears earlier or is more severe in succeeding generations. h. A gene affects more than one phenotype. i. The genotype of the maternal parent influences the phenotype of the offspring.

The \(L^{\mathrm{M}}\) and \(L^{\mathrm{N}}\) alleles at the MN blood-group locus exhibit codominance. Give the expected genotypes and phenotypes and their ratios in progeny resulting from the following crosses. a. \(L^{\mathrm{M}} L^{\mathrm{M}} \times L^{\mathrm{M}} L^{\mathrm{N}}\) \(\mathbf{b .} L^{\mathrm{N}} L^{\mathrm{N}} \times L^{\mathrm{N}} L^{\mathrm{N}}\) \(\mathbf{c .} L^{\mathbf{M}} L^{\mathbf{N}} \times L^{\mathbf{M}} L^{\mathbf{N}}\) \(\mathbf{d .} L^{\mathrm{M}} L^{\mathrm{N}} \times L^{\mathrm{N}} L^{\mathrm{N}}\) \(\mathbf{e} . L^{\mathrm{M}} L^{\mathrm{M}} \times L^{\mathrm{N}} L^{\mathrm{N}}\)

Assume that long ear lobes in humans are an autosomal dominant trait that exhibits \(30 \%\) penetrance. A person who is heterozygous for long ear lobes mates with a person who is homozygous for normal ear lobes. What is the probability that their first child will have long ear lobes?