PEDIGREES....... please help!

[clc8503]

I am having trouble with the pedigree problems on the MCAT and the current MCAT prep manual that I am using (REA) barely even says anything about them. I can somewhat understand how to do them but I am by no means comfortable with them. I flipped through my General Biology book and it also lacks a great deal about pedigrees in general. It just covers the most basic concepts of genetics and barely touches on pedigree solving strategies. Genetics is not part of my curriculum and there's no way I can fit the class in before I take the MCAT (maybe afterwards when things slow down). I've also heard people say on SDN that the pedigrees on on the MCAT are fairly simple if you know what you're doing. (easy points I've heard some people call them). This is definitely not the case with me! What prep guide explains pedigrees to the level that I will need to understand them for the MCAT? I'm desperate.

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[jochi1543]

I would try going to the campus library and checking out a genetics textbook. It's kind of hard to explain over the internet without a specific example, but if you find examples you have a hard time understanding, I'd help you if you posted them.

 

[scotties123]

i primarily use EK to study, and they dont teach pedigrees at all. funny thing is, they still give a pedigree problem in their question sets. This is how they basically work:
Square = Male
Circle = Female
Dark = expressing particular phenotype (typically (not always) homozygous recessive genotype)
White = expressing "normal" phenotype
Half shaded = carrier (i.e. have recessive gene but dont express, seen with x linked phenotypes, only females can be carriers, males ALWAYS express).
If given a pedigree and asked genotype of a particular individual, just backtrack and look at the parents of the individual. From there u can deduce if the parents are homozygous recessive, heterozygous, or homozygous dominant (usually not this one) by looking at offspring. Keep in mind that two heterozygous parents can have 4 children ALL normal phenotype. However, according to genotypic ratios, it would be expected that 1/4 offspring have recessive phenotype.
Hope that helps.

 

[Nikki2002]

yes get a basic genetics textbook--that will help you more than anything

 

[PseudomonasPAO1]

Here's a link with some good pedigree practice problems..They are more appropriate for a 3000 level genetics class, but good practice nonetheless:

http://www.mhhe.com/biosci/genbio/biolink/j_explorations/ch12expl.htm

Enjoy!

 

[olemissbabydoc]

Here's a link with some good pedigree practice problems..They are more appropriate for a 3000 level genetics class, but good practice nonetheless:

http://www.mhhe.com/biosci/genbio/biolink/j_explorations/ch12expl.htm

Enjoy!

great link! thanks!