Autosomal and X-linked genetics problem

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  • Thread starter Intr3pid
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In summary: Anyway, if you know how to do a Punnet square, you can work out the genotypes of the offspring just fine.
  • #1
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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  • #2
can someone please provide me some hints?
I'm very stressed out about this question.
 
  • #3
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.
 
  • #4
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.
 
  • #5
help please?
 
  • #6
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:
  • #7
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.
 

1. What is the difference between autosomal and X-linked genetics?

Autosomal genetics refers to traits and disorders that are determined by genes located on the autosomes, or non-sex chromosomes. These traits and disorders can affect both males and females equally. X-linked genetics, on the other hand, refers to traits and disorders that are determined by genes located on the X chromosome. These traits and disorders can affect males and females differently due to the presence of only one X chromosome in males.

2. How are autosomal and X-linked traits inherited?

Autosomal traits are inherited in a Mendelian pattern, meaning that they follow predictable patterns of inheritance based on the dominant and recessive nature of the genes. X-linked traits are also inherited in a Mendelian pattern, but due to the presence of only one X chromosome in males, they may appear to skip generations or be more prevalent in males.

3. Can autosomal or X-linked traits skip generations?

Yes, both autosomal and X-linked traits can skip generations. Autosomal traits may skip generations if the gene is passed down through carriers, who do not exhibit the trait themselves. X-linked traits may skip generations if the gene is passed down through females, who may be carriers and not exhibit the trait themselves, or if the gene is passed down through males, who only have one X chromosome.

4. What is the likelihood of inheriting an autosomal or X-linked trait?

The likelihood of inheriting an autosomal or X-linked trait depends on the specific trait and whether it is dominant or recessive. For autosomal traits, the chance of inheriting a dominant trait is 50%, while the chance of inheriting a recessive trait is 25%. For X-linked traits, the chance of inheriting a dominant trait is 50% for females and 100% for males, while the chance of inheriting a recessive trait is 25% for females and 50% for males.

5. Can autosomal or X-linked traits be passed down from one generation to the next?

Yes, both autosomal and X-linked traits can be passed down from one generation to the next. However, the presence of the trait in each generation may vary depending on the inheritance pattern and the sex of the individuals involved. It is also possible for a trait to skip generations or appear to "disappear" in a family due to carrier status or other factors.

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