Autosomal and X-linked genetics problem

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SUMMARY

The discussion focuses on solving a genetics problem involving the fruit fly Drosophila melanogaster, specifically addressing the inheritance of autosomal and X-linked traits. The participants clarify that the vestigial wings (vg) are recessive to normal wings (vg+) and the white eye trait (w) is recessive to red eyes (w+). The genotypes of the parents are established as WWrr for the homozygous white-eyed, long-winged female and wwRY for the homozygous red-eyed, vestigial-winged male. The use of a Punnett square is recommended for determining the F1 and F2 genotypes and phenotypes.

PREREQUISITES
  • Understanding of Mendelian genetics principles, including dominant and recessive traits.
  • Familiarity with Punnett squares for predicting genetic crosses.
  • Knowledge of sex-linked inheritance, particularly in Drosophila.
  • Ability to interpret genetic notation and symbols used in genetics.
NEXT STEPS
  • Practice constructing Punnett squares for dihybrid crosses involving both autosomal and X-linked traits.
  • Study the law of independent assortment and its application in genetic crosses.
  • Explore the genetic notation conventions used in Drosophila genetics.
  • Review examples of genetic problems involving multiple traits to enhance problem-solving skills.
USEFUL FOR

Students studying genetics, particularly those focusing on Drosophila melanogaster, educators teaching Mendelian inheritance, and anyone needing clarification on autosomal and X-linked trait interactions.

Intr3pid
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Homework Statement


In the fruit fly drosophila melanogaster, vestigial (partially formed) wings (vg) are recessive to normal long wings (vg+) and the gene for this trait is autosomal. The gene for the white eye trait (w = white is recessive to w+ = red) is located on the X chromosome. Suppose a homozygous white-eyed, long winged female fly is crossed with a homozygous red-eyed, vestigial winged male.

a) What will the genotypes and phenotypes of the F1 flies?

b) What will the genotypes and phenotypes of the F2 flies?

c) What will the genotypes and phenotypes of the the offspring of separate crosses of the F1 flies back to each appropriate parent?



Homework Equations


none



The Attempt at a Solution


I know how to deal with autosomal and X linked trait questions individually but I don't know how to solve the question when both autosomal and X linked traits are involved.

Help is appreciated. Thanks
 
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can someone please provide me some hints?
I'm very stressed out about this question.
 
You set up the problem very much the same way as if it were autosomal or x-linked only. Try using a Punnet square to work it out as if it were any other autosomal two-trait cross, but use a symbol for the sex-linked traits that reminds you which chromosome they came from.
 
Moonbear said:
You set up the problem very much the same way as if it were autosomal or x-linked only. Try using a Punnet square to work it out as if it were any other autosomal two-trait cross, but use a symbol for the sex-linked traits that reminds you which chromosome they came from.

Can you give me a few more hints or explanations?
I'm still really confused.
 
help please?
 
If you know how to deal with them individually, you're going to be fine... remember the law of independent assortment?

I think part of the problem is the very strange allelic naming system... the standard is to use the first letter of the dominant trait and for Capital letters to be dominant and lowercase letters to be recessive...
ok other than that I think I can get you started without giving too much away: based on the information in the question I'd wager that the genotypes of the parents are: using W = Long Wing (w = recessive vetigial wing) and R=Red eye (r = recessive white eye) and remember Y=male
we have a white eyes long winged female and we are told it is homozygous so: (WWrr) must be the genotype
and red eyed vestigial winged male (also homozygous) must be (wwRY)
simply do a dihybrid cross from there, and let us know if you need some more help.
 
Last edited:
Thanks for jumping in Oaksinstructor. Sorry for not being able to get back sooner Intr3pid, I was away for a few days for the holiday. Yes, I think the unusual naming convention is causing added confusion...too many letters to get confused.
 

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