Colour in a type of flower is controlled by two genes that...

Colour in a type of flower is controlled by two genes that together lead to four unique colours of petals. The “A” allele of gene 1 produces the dominant phenotype, blue flowers. The “B” allele of gene 2 produces the dominant phenotype, red flowers. When both alleles occur together (A_B_) the flowers are yellow. In the absence of either allele “A” or “B”, the flowers are mauve (aabb). You are given some seeds that were produced by a yellow-flowered plant, and plant them in your garden. Once the plants have grown and the flowers are blooming, you find every one of the four colours in your garden. When you count the plants, you find 22 yellow, 19 blue, 21 red, and 23 mauve. What can you deduce about the genotypes of the parent plants? What colour (phenotype) was the other parent plant? Explain your answers in clear detail using a couple paragraphs. Use a Punnett square to help you understand.

Transcript

00:01 Hi all, so here we are asked a genetics question.

00:04 So in the question it is said that color in a type of flower is controlled by two genes, controlled by two genes that together will yield to four unique colors of petals.

00:23 So here there is the a allele which is controlled by the gene 1 and they produces the dominant phenotype that is the blue flower.

00:41 Now next is the b allele of the gene 2 and they produces the dominant phenotype of the red flower.

00:59 When both alleles occur together the flowers are yellow that is if both the alleles that is a and b allele is there then the flowers were yellow, there produced the yellow flower and in the absence of either a or b allele the flowers are mauve.

01:28 So here the genotype shown is dominant, sorry recessive allele they shows the mauve flower, mauve flower.

01:41 So you are given some seeds that were produced by the yellow flowered plant and plant them in your garden.

01:49 So once the plant have grown and flowers are blooming you find every one of the four colors in your garden that is blue, red, yellow and mauve.

01:58 So when you count the plants you find yellow flower plant was 22, then blue obtained was 19 and red was 21 and mauve was 23.

02:17 So we are here asked what can you deduce about the genotype of parent plant and what color was the other parent plant.

02:28 So we'll see so these are all the information which is given in the question.

02:35 Now let's deduce the genotype of the parent plants by step by step.

02:39 So we'll see first one is the yellow flower, yellow flower.

02:46 So here yellow flower results from the presence of both dominant allele that is the a and b and there are 22 yellow flower, yellow flowered plants.

03:02 So these plants must have at least one a allele and one b allele.

03:09 So we can say that these yellow flower that is 22 yellow flower have this a and b allele.

03:18 Now for blue flower, now for the blue flower, this blue flowers are produced when there is a a allele from the gene 1 and two recessive alleles from gene 2, two recessive alleles from gene 2.

03:39 So recessive alleles which might be represented as lowercase b from the gene 2.

03:46 So the blue flower were 19, so we can say that there were 19 blue flowered plants...

Question

Please give Ace some feedback