Question

Web Genotypes and phenotypes for some common single gene inheritance patterns. Inheritance Pattern Genotype Phenotype Affected Affected Not affected AA Autosomal Dominant Aa aa NN Not affected Not affected Affected Autosomal Recessive Nn nn XXN XNX Normal female Normal female Affected female Normal male Affected male Sex-linked Recessive X"X xNY X"Y Pedigree Analys is Instructions: 1. Examine the following three pedigrees. 2. Determine the most probable pattern of inheritance for each pedigree and record it in the space provided at the top of each pedigree. 3. Determine the genotype of each individual in each pedigree. Using the appropriate allele symbols in the table, above, record the genotype next to each person in pedigrees 1-3, below. Pedigree #1 Most probable pattern of inheritance: Male Female Normal Affected dora

Answer 1

Taking the generation 1of family 1 on the pedigree, the possible genotypes of generation 2 of the pedigree chart:(assuming the trait to be autosomal recessive)[father= Nn, mother= nn]

	N	n
n	Nn(normal)	nn(affected)
n	Nn(normal)	nn(affected)

For generation 3:[father = nn, mother= Nn]

	n	n
N	Nn(normal)	Nn(normal)
n	nn(affected)	nn(affected)

For the Family 2 of the next pedigree: [ father=nn, mother= NN]

	N	N
n	Nn(normal)	Nn(normal)
n	Nn(normal)	Nn(normal)

For 4th generation:(daughter of family 1 x son of family 2; father= Nn, mother = Nn)

	N	n
N	NN(normal)	Nn(normal)
n	Nn(normal)	nn(affected)

Hence we see that the pattern of inheritance is AUTOSOMAL RECESSIVE.

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