## Help to another pedigree

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

mensamedlem
Garter
Posts: 32
Joined: Sun Mar 22, 2009 7:42 am

### Help to another pedigree

I need help to find the answer to the questions below this text:

1) Which genotypes do the persons have?

2) What proportion of the offspring from the individuals III-1 and III-2 are likely to have the disease?

3) What proportion of the offspring from the individuals III-6 and III-7 are likely to have the disease?

http://www.flickr.com/photos/[email protected]/4119434147/

Squares = males. Circles = females.
Yellow = sick. Green = healthy.

Can you help me?

mensamedlem
Garter
Posts: 32
Joined: Sun Mar 22, 2009 7:42 am
My guesses are:

1) Which genotypes do the persons have?

All the sick individuals will be Aa and the healthy will be aa.

2) What proportion of the offspring from the individuals III-1 and III-2 are likely to have the disease?

Aa x aa = 1/2 = 50 percent.

3) What proportion of the offspring from the individuals III-6 and III-7 are likely to have the disease?

Aa x Aa = 3/4 = 75 percent.

JackBean
Inland Taipan
Posts: 5694
Joined: Mon Sep 14, 2009 7:12 pm
The very first sick person should be probably AA, as both children are sick (but guessing from only 2 children is kind of not perfect;)
2 and 3 probably correct
http://www.biolib.cz/en/main/

Cis or trans? That's what matters.

mensamedlem
Garter
Posts: 32
Joined: Sun Mar 22, 2009 7:42 am
Thank you!

mensamedlem
Garter
Posts: 32
Joined: Sun Mar 22, 2009 7:42 am
Is what I have written correct?

Figure 2: http://www.flickr.com/photos/[email protected]/4119434147/

The inheritance is dominant because genes partitions are not skipped and sick children have sick parents. It can not be x-linked since sick boys fathers are also sick. This is because the boy gets his Y chromosome through the father's sperm while the good x-chromosome from her mother's eggs.

JackBean
Inland Taipan
Posts: 5694
Joined: Mon Sep 14, 2009 7:12 pm
you're too generalizing. What if the first one is ill homozygote and the second one is healthy but heterozygote?
http://www.biolib.cz/en/main/

Cis or trans? That's what matters.

mensamedlem
Garter
Posts: 32
Joined: Sun Mar 22, 2009 7:42 am
What can I write instead of this?

JackBean
Inland Taipan
Posts: 5694
Joined: Mon Sep 14, 2009 7:12 pm
That it's dominant, because (your text) and because half of offspring is affected (if it was recesive, it would be only 1/4;)
http://www.biolib.cz/en/main/

Cis or trans? That's what matters.

mensamedlem
Garter
Posts: 32
Joined: Sun Mar 22, 2009 7:42 am
Is my definition of that it cannot be x-linked correct?

JackBean
Inland Taipan
Posts: 5694
Joined: Mon Sep 14, 2009 7:12 pm
basically... I would say, that even ill men have healthy boys Simpler and easier
http://www.biolib.cz/en/main/

Cis or trans? That's what matters.

mensamedlem
Garter
Posts: 32
Joined: Sun Mar 22, 2009 7:42 am
Is my answer to the fact that it cannot be x-linked correct? Yes or no?

JackBean
Inland Taipan
Posts: 5694
Joined: Mon Sep 14, 2009 7:12 pm
With closing both eyes, it's relativelly fine... but definitively not perfect
The idea is fine, but not so much, how did you write it
http://www.biolib.cz/en/main/

Cis or trans? That's what matters.

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