The smooth feathers on the back of the neck in pigeons can be reversed by a mutation to produce a 'crested' appearance in which feathers form a distinctive spike at the back of the head. A pigeon breeder examined offspring produced by a single pair of non-crested birds and recorded the following: 22 non-crested and 7 crested. She then made a series of crosses using offspring from the first cross. When she crossed two of the crested birds, all 20 of the offspring were crested. When she crossed a non-crested bird with a crested bird, 7 offspring were non-crested and 6 were crested. For these three crosses, provide genotypes for parents and offspring that are consistent with these results.

Video transcript

Hello everyone here we have a question telling us. A researcher sets three mating pairs and her observations are as follows. Experiment one male mouse having brown fur made it with a female mouse having brown for the observations. 10 pups had brown fur and three had white. For experiments to male mouse having white fur made it with a female mouse having white For all. The eight pups have white fur. Experiment three male mouse having brown fur made it with a female mouse having white for observation. Five pubs had brown fur and four had white for identify the correct genotype of the parents for each of these experiments. So an experiment one we observe tim pucks having brown fur and three having white fur which means brown fur is dominant and white fur is recessive. So in this case we have two hetero zigo's say goats for brown fur. So capital B. Lowercase B. Times capital B. Lowercase B. And that gives us capital B. Capital B. Which will be brown for home. A zygote. Capital B. Lowercase B. Which be brown for hetero Zago, Capital B. Lower case B. Lower case B. Lower case B. So we have white fur which is lower case B. Lower case B. We have three of them and brown for which is capital B. Capital B. Or capital B. Lower case B. We have 10. So our ratio is 3-1. And then we have experiment too. And it was two white mice. So that has to be hetero zygote because white is recessive. So lower case. B. Lower case B. Times lower case B. Lower case B. And that gives us lower case B. Lower case B. Lower case B. Lower case B. Lower case B. Lower case B. Lower case B. Lower case B. So there will be zero with brown fur and they will all have a bite for. And lastly we have experiment three which we have a male mouse having brown fur made with a female mouse having white fur. And five of the pups have brown fur and four have white fur. So we have a hetero zygote for brown fur and the mother was white so lower case B. Lower case B. And that gives us capital B. Lower case B. Capital B. Lower case B. Lower case B. Lower case B. Lower case. B. Lower case. B. So brown for or capital B. Lower case B. We have five white for or lower case B. Lower case B. We have four And our ratio is 1 - one. So our answer here is C. Experiment one capital B. Lowercase B. Times capital B. Lowercase B. Experiment to lower case. B. Lower case B. Times lower case B. Lower case B. And experiment three. Capital B. Lowercase B. Times times lower case B. Times lower case B. Thank you for watching. Bye.