Biology

posted by .

I have to draw a mating diagram to show a cross between two heterozygotes for lactose production. As both adults have the dominant allele L for persistant lactase production would I start the diagram with LL for each parent?

Yes, if you mean production. Lactose digestion genetics is quite a different matter, and more complicated.

Thankyou so much. For the next question I have to draw a similar diagram to show the cross between a person with lactose intolerance and one who is heterozygous. This would mean starting with one parent LL and one parent ll? The text book I've been given does not explain it very well.

I have completed the first diagram and I have to state the phenotypic and genotypic ratio of the offspring in the F1 generation. As the offspring will all be LL, how can I determine the ratio? I can work out the ratio for the lactose intolerant and heterozygous cross ok, but I'm not sure how to do this if all the offspring are the same!

Just realised where I was going wrong. Two heterozygotes crossed would start with Ll for each parent, giving a phenotypic ratio of 3:1 for the F1 offspring.

Correct.

Respond to this Question

First Name
School Subject
Your Answer

Similar Questions

  1. biology

    Help needed to 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 …
  2. Genetics/biology

    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 …
  3. Genetics/biology Advice

    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 …
  4. Biology

    Hi! If I have two plants with the genotypes Rrtt and rrTt where red color(R) is dominant over white(r) and being tall(T) is dominant over being short(t).If I complete a Punnet square, will it look loke this: R r r r t Rt rt T rT rT …
  5. biology

    consider two plants wuth the genotypes Rrtt and rrTt where red color (R) is dominant over white (r) and being tall (T) is dominant over being short (t). complete the punnett squares to determine the possible ganetes each parent could …
  6. Biology

    Your research team suspects that lactose intolerance is a recessive trait. Which of the following observations would contradict your theory?
  7. Science

    In humans, having dimples is a dominant trat. In order for a child to have dimples A. at least one parent must not have dimples and pass on the recessive allele. B. both parents must not have dimples and pass on the recessive allele. …
  8. Biology

    Pod color and pod shape were two other traits Mendel was interested in. Set up a dihybrid cross for these two traits. Note: Green pods are dominant over yellow pods and inflated pods are dominant over constricted pods. -Start off with …
  9. Science

    2. Which of the following describes the genotype and phenotype of parents whose child will definitely have a recessive trait?
  10. bio

    A large population of laboratory animals has been bred randomly for a number of generations. There was an interesting revelation. The scientists noted that there was neither an increase nor a decrease in the frequency of animals displaying …

More Similar Questions