Fill in the blanks in the following sentences using one of t

Fill in the blanks in the following sentences using one of the following terms: a. Hereditary retinoblastoma is an autosomal dominant form of cancer. However, approximately 10% of individuals who carry the Retinoblastoma allele do not develop cancer of the eye. This is because the dominant allele shows ___. b. The I^A and I^B blood group alleles are an example of alleles which show: ___. c. Porphyria is a genetic disease which affected King George III. The disease has many different symptoms including abdominal pain, fever, insomnia, convulsions and dark red urine. This is an example of: ___ d. Transmission of genes in mitochondrial or chloroplast DNA is known as ___. e. A is used to check whether two mutants have mutations in the same gene or in different genes. f. Milk yield in dairy cows is an example of a: ___.

Solution

a. Hereditary retinoblastoma is an autosomal dominant form of cancer. However, approximately 10% of individuals who carry Retinoblastoma allele don’t develop cancer of the eye. This is because the dominant allele shows incomplete penetrance. Incomplete penetrance is a condition in which a gene that is not phenotypically expressed in all members of a family with the disease causing gene.

b. The IA and IB blood group alleles are an example of alleles which show codominance. When both alleles of a pair are fully expressed in a heterozygote, they are called codominant alleles.

c. Porphyria is a genetic disease which affected King George III. The disease has many different symptoms including abdominal pain, fever, insomnia, convulsions and dark red urine. This is an examples of sex-linked trait i.e. X-linked dominant inheritance.

d. Transmission of genes in mitochondrial or chloroplast DNA is known as cytoplasmic inheritance or Extrachromosomal inheritance and is an example for non-Mendelian inheritance.

e. A complementation test is used to check whether two mutants have mutations in the same gene or in a different gene.

f. Milk yield in dairy cows is an example of maternal effect. It is a trait controlled by a gene of mother but expressed in progeny.