Question

Please help solve this lab question:

Two breeds if dogs, one with straight black fur and the other with curly brown fur, were crossed. The hybrids were crossed next, and produced the following progeny:

30. Two breeds of dogs, one with straight black fur and the other with curly brown fur, were crossed. The hybrids were crossed next, and produced the following progeny: 179 Brown, straight Brown, curly Brown, wavy 35 29 62 black, wavy black, straight black, curly a. Propose a hypothesis to explain these results. b. What was the phenotype of the F1 animals? C. Test your hypothesis using a chi square and indicate whether you support your null hypothesis or reject it. d. What fundamental principles or laws are illustrated by this data?

Answer 1

a. Black hair is dominant to brown hair. Where as the straight and curly hair are incompletely dominant to each other.

b F1 animals are black with wavy hair.

c.

co Qara?w - у 99 Phenotype role (O-E) (0-E)? 1. Co- Brist 35 30.5 4.5 20.25 0.66 | в Си 130.5 -1.5 2.25 | 0.07 BY, W 62 61.1 10.9 | 0.01 3. ) 179 183-3-4 16 0.87 Blis 75 | 91.7 3.3 10.89 0.118 Be, c | 89 | 91.7 -2.7 7.29 | 0.07 10. 81 Ma 0.66 +0:67 +0.01 -0.87 +0.118 + 0.07 51.798 df = 5 P=11.07

Chi-square value is much less than the P value from tables. So we fail to reject Null hypothesis. We conclude that the difference in expected and observed are due to chance and have no significance. We support Null hypothesis.

d. The laws that can be illustrated by this is the law of dominance and Law of independent assortment.