Can anyone comment as to wether this solution is correct for this question please !!
Draw a mating diagram where L is the dominant gene for the digestion of lactose and shows the crosses between two heterozygotes and wiht the the phenotypic and genotypic ratio of the offspring in the F1 generation.
I also need to know the phenotypic prportions of the offspring of another cross between a person with lactose intolerance and one who is heterozyous.
Heterozygote (both male and female) Lactose tolerant
Male L l gametes
Female
L l gametes
To draw a mating diagram and determine the phenotypic and genotypic ratio of the offspring, we need to understand the inheritance pattern of the gene for lactose digestion.
In this case, the gene for lactose digestion has two variations or alleles: L (dominant allele for lactose tolerance) and l (recessive allele for lactose intolerance).
Cross between two heterozygotes (Ll x Ll):
To draw the mating diagram, we represent the parents as Ll x Ll, indicating that both parents are heterozygous for the gene.
To determine the genotypic and phenotypic ratios of the offspring, we can use a Punnett square. The Punnett square is a method used to predict the possible combinations of alleles from the parent gametes.
| L | l |
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L | LL | Ll |
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l | Ll | ll |
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From the Punnett square, we can see that there are three possible genotypes in the F1 generation: LL, Ll, and ll. The genotypic ratio is 1:2:1, meaning there is a 25% chance of getting LL, 50% chance of getting Ll, and 25% chance of getting ll.
Since the L allele is dominant, individuals with either LL or Ll genotypes will be lactose tolerant, and individuals with ll genotype will be lactose intolerant. Therefore, the phenotypic ratio is 3:1, indicating that 75% of the offspring will be lactose tolerant, and 25% will be lactose intolerant.
Cross between a lactose intolerant person and a heterozygous person (ll x Ll):
To determine the phenotypic proportions of the offspring, we again use a Punnett square. We represent the lactose intolerant person as ll and the heterozygous person as Ll.
| L | l |
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l | Ll | ll |
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From the Punnett square, we can see that there are two possible genotypes in the offspring: Ll and ll. Since the l allele is recessive and ll genotype results in lactose intolerance, all the offspring will be lactose intolerant. Therefore, the phenotypic proportions in this cross will be 100% lactose intolerant.
I hope this helps you understand how to approach solving this question and draw the relevant mating diagrams.