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Biology-Related Homework Help Genetics and Developmental Biology Topic started by: samantacastillo on Jan 15, 2023



Title: 2nd Part need help now
Post by: samantacastillo on Jan 15, 2023
1) There is a lack of dominance in four o’clock plant flowers. When a red flower is crossed with a white flower, a pink flower is produced.

In an experiment, pink flowers were self-pollinated. The phenotype ratio of the offspring is

Number:            Answer.        Answer     Answer
Flower Colour:  Pink               White        Red       



2) Feather colour in birds is controlled by two genes on separate chromosomes. Blue colour (B) is dominant over the absence of colour (b). Red colour (R) is dominant over the absence of colour (r). When a B allele and an R allele are present, a purple feathered bird is produced.

A heterozygous purple bird was crossed with a blue-feathered bird. One white-feathered offspring resulted from the cross. What is the genotype of the blue-feathered bird?
(3 marks - 2 marks for the correct genotype with an explanation as to how you determined your answer, 1 mark for the Punnett square)


Title: Re: 2nd Part need help now
Post by: Angelangels on Jan 15, 2023
#1

Since breading the red flower with the white flower resulted in pink flower, this indicates a codominance (both alleles are expressed) in a heterozygous plant. The phenotype is deduced to RW (R for red and W for white). Self breading you are crossing RW x RW you have 4 possible outcomes, 25% of the time you'll get RR with a red phenotype, 25% of the time you'll get WW with a white phenotype, and 50% of the time you'll get RW with a pink phenotype.

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#2

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