Genetics Problem!!!

Genetics as it applies to evolution, molecular biology, and medical aspects.

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Kirstencheese
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Genetics Problem!!!

Post by Kirstencheese » Tue Sep 25, 2007 10:48 pm

I have a problem that I am REALLY confused about! PLEASE help me! Okay, so here goes: In sesame plants, the one-pod condition (P) is dominant to the three-pod condition (p), and a normal leaf (L) is dominant to wrinkled leaf (l). Pod type and leaf type are inherited independently. Determine the genotypes for the two parents for all possible matings producing the following offspring:
a) 318 one-pod normal, 98 one-pod wrinkled
b) 323 three-pod normal, 106 three-pod wrinkled
c) 401 one-pod normal
d) 150 one-pod normal, 147 one-pod wrinkled, 51 three-pod normal, 48 three-pod wrinkled
e) 223 one-pod normal, 72 one-pod wrinkled, 76 three-pod normal, 27 three-pod wrinkled
I got a and b, but I'm not sure they're right, and I have NO IDEA on the rest! Got a) PpLl & PpLl, b) ppLl & ppLl. ??? Please help fast!!!!

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mith
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Post by mith » Tue Sep 25, 2007 11:33 pm

a is wrong since Pp X Pp would also produce 3 pod offspring.
c. to produce one pod you need parents that don't produce pp offspring. to produce normal you need parents that don't produce ll offspring. So actually there are a couple of valid answers.


For the rest of the questions, here's what I suggest: separate out the phenotypes so for d you'd be dealing with 150 normals , 147 wrinkled, 51 normal and 48 wrinkled. Add up and you can tell that wrinkled and normal are 1:1 meaning its a Pp X pp cross. Then similarly do the same for pod type.
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Kirstencheese
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Post by Kirstencheese » Wed Sep 26, 2007 10:53 am

Thank you so much! I'm still not sure I completely get it, but I have at least a better idea of what to do! But, my teacher said that a was right, but I checked it, and you are right. I'm going to talk to her, because I don't get how her answer could be correct. I really appreciate your help!

Pharmacy_Man2007
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Post by Pharmacy_Man2007 » Sun Oct 21, 2007 1:26 am

You only have to apply the FIRST and the Second Law of Mendel By doing The Crossings... You determine who is Male and Female P: P1 X P2 (Lignée Pure) , The Parents which Give the First Generation F1 ( Hybridations)

If You do a Crossing Over, you Cross the F1 with the Recessive Phenotype ,Then if it is a Intrachromosomic brassage, you find a non_equiprobability, if it is an interchomosimical brassage, it is equibrobable for F2

If You Cross F1 x F1, you obtain different percentage of F2

The First law of mendel= Purety of the Gametes
The Second law= Independent Segregation of the couples of the caracteres

ok? ( Sorry because i come from france and i try to learn about english in scientific vocabulary :D

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