Genetics assignment two Essay Example | Topics and Well Written Essays - 500 words

Genetics assignment two - Essay Example sive alleles of each of these genes (a,b,c and d) produce abnormal enzymes that cannot catalyze a reaction in the biosynthetic pathway for seed pigment. The pathway is shown below: 2. In the Australian Shepherd, Hereditary Cataracts is an autosomal dominant disorder that results in abnormal clouding of the lenses of the eye. In some Aussies, heterozygous for Hereditary Cataracts, the disease is not always expressed. Based on this information, answer the following questions: b. Several alleles are responsible for Hereditary Cataract formation. When present, some alleles result in very rapid cataract growth, whereas; other alleles result in very slow cataract growth. What terminology best describes the behavior of these various alleles? 3. In the oriental fruit fly (Bactrocera dorsalis), a number of genes determine eye color. A fly with wild-type eyes (red) is crossed to fly with yellow eyes. All the F1 flies from this cross have wild-type eyes. When the F1 from the cross are interbred (selfed), 450 of the progeny have wild-type eyes, 150 have amethyst eyes (a bright sparkling blue color) and 200 have yellow eyes. 4. The Scots Dumpy, a type of chicken from Scotland, can exhibit short-leg length and normal-leg length phenotypes. A breeder crosses two normal-legged Scots Dumpy, and finds that all of the F1 are normal-legged. The breeder repeats the cross and observes the same result. However, when the same breeder crosses a normal-legged fowl with a short-legged fowl,  ½ of the offspring are short-legged and  ½ of the offspring are normal-legged. Finally, following a third cross between two short-legged Scots Dumpy fowl, the breeder observes the following results among 200 offspring counted: 5. Fruit flies homozygous for the recessive allele, sc-, have bright red eyes. Fruit flies homozygous for the recessive allele, br-, have brownish purple eyes. Fruit flies homozygous recessive for both alleles have white eyes. Fruit flies that possess the sc+ and