BIOL201 Lecture Notes - Mendelian Inheritance, Melanin, Zygosity
11 Apr 2014
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Biology 207 - practice questions 5 - mendelian genetics - answers. Question 1 type i albinism is caused by the absence of the enzyme tyrosinase which converts the amino acid tyrosine into the pigment melanin. Tyr gene at 11q14-q21: describe the gene"s cytologtical location. People with one functioning copy of the gene have a wt phenotype because this allele can make a sufficient amount of tyrosinase. Question 2 both members of an edmonton couple are heterozygous for recessive mutations in the tyr gene. They have two children: write out the genotype and phenotype for each parent. 1/4: what is the probability that both children are albino? p(both children albino)= p(1st child albino) x p(2nd child albino) = 1/16: what is the probability that both children are phenotypically identical with regard to skin color? p(phenotypically identical) = p(both albino) + p(both non-albino)
