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A trait in a family is investigated. Both parents are heterozygous for the trait. Their offspring demonstrate a 3 to 1 ratio of trait expression to non expression The most likely route of inheritance is?
a) autosomal dominant
b) autosomal recessive
c) sex linked
d) random mutation

Curly wings in drosophila is due to a rare inherited trait. A curly winged female mates with a straight winged male. One half of the offspring produced male and female, are curly winged. The gene that determines this characteristic is probably
a) autosomal dominant
b) autosomal recessive
c) sex linked recessive
 
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a and c?
 

tncekm

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(1) A -- 3/4 of the offspring show the trait, that means that AA, Aa, aA (same thing) all show trait while aa doesn't. For Aa or aA (again, same thing essentially, just putting it there for the understanding it imparts) to show the trait, it must be dominant.

(2) A or B -- Female = curly, Male = Not curly; Most likely we're seeing a heterozygote (Aa or aA, again same thing) and recessive (aa) crossing to propagate the offspring that exhibit both traits in a 50:50 ratio.

Aa x aa = Aa,aA,aa,aa = 50% Aa, 50% aa, or a 1:1 ratio. If it was sex-linked, you typically see different expression patterns in male than female, but the expression was the same. So, it's not c.

Not enough info given.
 
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akeurogh

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(1) A -- 3/4 of the offspring show the trait, that means that AA, Aa, aA (same thing) all show trait while aa doesn't. For Aa or aA (again, same thing essentially, just putting it there for the understanding it imparts) to show the trait, it must be dominant.

(2) B -- Female = curly, Male = Not curly; Most likely we're seeing a heterozygote (Aa or aA, again same thing) and recessive (aa) crossing to propagate the offspring that exhibit both traits in a 50:50 ratio.

Aa x aa = Aa,aA,aa,aa = 50% Aa, 50% aa, or a 1:1 ratio. If it was sex-linked, you typically see different expression patterns in male than female, but the expression was the same. So, it's not c.
:thumbup::thumbup:
 

Maygyver

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(1) A -- 3/4 of the offspring show the trait, that means that AA, Aa, aA (same thing) all show trait while aa doesn't. For Aa or aA (again, same thing essentially, just putting it there for the understanding it imparts) to show the trait, it must be dominant.

(2) B -- Female = curly, Male = Not curly; Most likely we're seeing a heterozygote (Aa or aA, again same thing) and recessive (aa) crossing to propagate the offspring that exhibit both traits in a 50:50 ratio.

Aa x aa = Aa,aA,aa,aa = 50% Aa, 50% aa, or a 1:1 ratio. If it was sex-linked, you typically see different expression patterns in male than female, but the expression was the same. So, it's not c.
:thumbup::thumbup: Just some simple punnett stuff.
 
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Maygyver! u just got wrong on just simple punnet stuff. Correct answer is 1. B 2. A
 
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sfoksn

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No, the answer key is incorrect.. A and B is correct for sure.
 

Maygyver

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Maygyver! u just got wrong on just simple punnet stuff. Correct answer is 1. B 2. A
Incorrect.Sex-linked will have a gender difference. Also, if you think the answers are wrong, just go off what your answer key says because most the time you won't even post answers here for people to help you with.
 
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Maygyver
U were on my ignore list, I will put u back on. You are always upset when you get wrong. You always complain when you can't find the answer. You always blame when you don't know something. You always says that's such an easy question.

Like I told you, there will be no belt for you, such an immature person !
I forward your black mailing on the board already, they are on investgating now, so sending a dirty mail me again.
 
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U were on my ignore list, I will put u back on. You are always upset when you get wrong. You always complain when you can't find the answer. You always blame when you don't know something. You always says that's such an easy question. I only post question when I don't have an answer or when I only have just answer. That's why I posted here. Like you said, its such an easy question, then why you got it wrong. :) and now you said the answer key is wrong? hell no, I know how to solve this question, I wanted to see different perspective from different people who is mature enough, not like you because a lot more times, I got better idea from smart people on this board. So be mature !

Like I told you, there will be no belt for you, such a immature person !
I forwarded your black mailing already, they are on investgating now, so stop sending a dirty mail me again.
 
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tncekm

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U were on my ignore list, I will put u back on.
No, really... if you get 3 expression, 1 non expression then the trait is always dominant. He's not wrong.

And with the second one, I just realized not enough info is given. You cross a heterozygote with recessive if you want to get 1:1 of Aa:aa, but that means curly can be either dominant (Aa) or recessive (aa). So, not enough information is given. You need to know what happens if you cross homozygotes (AA and aa) to determine if it's dominant v. recessive, and then the heterozygote cross Aa and aa, i.e. test cross, will allow you to determine if it's sex linked or not.

What book is this?
 
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tncekm, I am not saying his answer is wrong or not. He may or may not. My point is He always post some bad thing whenever I post something. He even mailed me with my first DAT score and laugh at me. I guess he has a sort of mental problem.

It came from HIGH YIELD biology (columbia Review) The same questions came from ADA sample test published about 1995 (don't know exact year) and also GRE biology 2005. They all have same answer.

Here is simple solution manual says
1. Recessive disorders skip generations because heterozygotes are carriers and are phenotypically normal. The trait is autosomal because the sex of the parents and offspring is unimportant.

2. Possessing curly wings in the first generation appears independent of sex. In addtion, one can expect to see carriers among females if sex linked recessive is the form of transmission. Therefore, a dominant form of transmission has occurred. Autosomal dominant transmission is plausible.
 
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Maygyver

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No, really... if you get 3 expression, 1 non expression then the trait is always dominant. He's not wrong.

And with the second one, I just realized not enough info is given. You cross a heterozygote with recessive if you want to get 1:1 of Aa:aa, but that means curly can be either dominant (Aa) or recessive (aa). So, not enough information is given. You need to know what happens if you cross homozygotes (AA and aa) to determine if it's dominant v. recessive, and then the heterozygote cross Aa and aa, i.e. test cross, will allow you to determine if it's sex linked or not.

What book is this?
Yeah, it looks like the second one you would need more info because you can only tell the two genotypes, but not which phenotype accompanies the genotypes.

Also, calm down kpark...
 

tncekm

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Yeah, it looks like the second one you would need more info because you can only tell the two genotypes, but not which phenotype accompanies the genotypes.

Also, calm down kpark...
I'll quote you since I think he blocked you. lol
 

Maygyver

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I'll quote you since I think he blocked you. lol
Hah thanks. Some people don't like people that tell things like they are I guess. Or maybe I actually do get really really mad over questions on forums... :p

Also, one thing I thought of, is that since it says it is rarely inherited, they might want you to assume that the allele is infrequent and then extrapolate that to the curly winged individual being the heterozygote since it would be more likely than it obtaining 2 of the rare alleles. Possibility?
 

UndergradGuy7

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A trait in a family is investigated. Both parents are heterozygous for the trait. Their offspring demonstrate a 3 to 1 ratio of trait expression to non expression The most likely route of inheritance is?
a) autosomal dominant
b) autosomal recessive
c) sex linked
d) random mutation

Curly wings in drosophila is due to a rare inherited trait. A curly winged female mates with a straight winged male. One half of the offspring produced male and female, are curly winged. The gene that determines this characteristic is probably
a) autosomal dominant
b) autosomal recessive
c) sex linked recessive
The answer key you said was B and A.

I think 1 should be A.
2 is A I think.

For 2 its not C, because males and females are equal. It is not B because I remember in genetics it says that it is a rare trait therefore it is a very low chance of having a heterozygous person. You should assume the person is homozygous for the trait (the man). So the man has to be xx. So if the man is normal and is xx then the lady is Xx and half their children are dominant Xx, while the other half is recessive xx. So answer A.

If you put Xx as the man and xx as the lady you would also get half the children to be effected, but this means the man is heterozygous for the trait. The trait in the problem says it is rare, therefore a heterozygous person is unlikely.
 

tncekm

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The answer key you said was B and A.

I think 1 should be A.
2 is A I think.

For 2 its not C, because males and females are equal. It is not B because I remember in genetics it says this is a rare trait therefore it is a very low chance of having a heterozygous person.
You're right that it's A in "real life", but this question should have provided more information if they expect a student to be able to figure out the answer.
 

dentalWorks

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Kpark102 ~

you shouldn't criticize people after coming here and posting a question about something you didn't want to spend the extra effort trying to get the correct answer yourself. You should underestand that whatever answers people give you on this forum are simply based on THIER BEST KNOWLEDGE, so wheater he was right or wrong, you should appreciate him taking the time to answer your question as best as he could
 
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A can be true if the Female is Aa, male AA. Offspring would be 50% Aa, 50% AA. This requires the assumption that the female is heterozygous, which is not given in the question.

B can be true if the female is aa, male Aa. Offspring would be 50% Aa, 50% aa. This requires the assumption that the male is heterozygous for the recessive trait, which again is not given in the question.

It can be argued that it's much more likely to have a heterozygous female with one copy of this rare allele than to have a female who is homozygous serendipitously mating with a male that happens to be heterozygous for the same rare allele. Either way the question doesnt give enough info to certainly say one and not the other.
 
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dental work ! I totally agree with you, but you don't know the history between me and him. I never criticized people here, but he did !

He even mailed me and laugh at me !!!!!!!!!!!!!!!!!!!!!! You don't know history do you? He act like good people now but do you want to see his mail???? I can forward to you if you want to see:) he has mental problem definitely,