<p>I am having trouble with pedigree charts. Does anyone know a place to learn them better? Like try to tell me this.
Do both the parent AND the offspring of an affect individual (w/ a disesase or w/e) have to have it in order for it to be dominant? Like pretend I had these
A - Parent
B - offspring
C - B's offspring
B has the disease
A and C don't
This is recessive
However what if I do this..
A - does not have
B - has
C - has
or
A - has
B - has
C - has
or finally
a - does not have
b - does not have
c - does have.</p>
<p>Can someone help me with this. I really hate pedigree charts. Are they on the test frequently?</p>
<p>Also do I have to know all these phylums under the kingdoms... like
under kingdom protista
phylum rhizopoda
etc etc.
Its gonna take a WHILE for me lol. Just wondering. Thanks.</p>
<p>NM about 2nd part (well please answer it but still) because I just realized we are doing a lOT of this stuff in zoology.</p>
<p>I just need a little more information, then I'll be able to help you. </p>
<p>Is A the grandparent of C?</p>
<p>What about the spouses of A and B- are they affected or not?</p>
<p>Spouses are not affected. And yes A is grandparent of C.</p>
<p>
[quote]
A - does not have
B - has
C - has
[/quote]
</p>
<p>The disease is recessive. Parent A and her spouse are heterozygous for the trait. (ex. Aa) They passed it on to parent B. Her husband is heterozygous for the trait and they passed it on to C.
The disease cannot be dominant because autosomal dominant traits don't skip generations.</p>
<p>
[quote]
A - has
B - has
C - has
[/quote]
</p>
<p>The trait has to be dominant. If the spouses of both parents are normal and the child still inherited it, the disease can only be dominant. </p>
<p>
[quote]
a - does not have
b - does not have
c - does have.
[/quote]
</p>
<p>The trait must be recessive. Parent A is heterozygous and caused B to be a carrier of the trait as well. Parent B and her spouse are heterozygous for the trait and passed it on the C.</p>
<p>Princeton review has a pretty good section in its SATII bio book that tells you how to deal with pedigrees. And yes, pedigrees regularly show up. There was one on the October 14th test just a few days ago (or maybe I'm getting it confused with one of the 8 practice tests that I took in the past 3 weeks, haha.) And on the phlum question, yeah, you should know those fairly well, too. On the SATII this past weekend, I think there were two questions that dealt with taxonomy.</p>
<p>Ok thanks. I studied PRS and its still a bit confusing. But its making more sense. Thanks people.</p>