What is a good example of dominant-recessive pattern of inheritance in
humans?  The child development text books use eye or hair color as
examples, but these both are really polygenic, or so I gather.  Is
there an accurate example of dominant-recessive genes in humans?

Hi Brendabb,

As a medical librarian I think quite often of typical
dominant-recessive diseases, but there are a lot of other traits that
follow this pattern. Here are some examples:

WrongDiagnosis.com: Autosomal Dominant Diseases
http://www.wrongdiagnosis.com/class/genetic_autosomal_dominant.htm
This page lists a variety of diseases (10 plus a class of additional
ones), each linked to a description of the disease, that are caused by
a dominant gene.  Polydactyly (multiple digits, either of fingers or
toes) is one of the most well-known.  This site focuses on diseases
that are commonly misdiagnosed, thus the name.

WrongDiagnosis.com: Autosomal Recessive Diseases
http://www.wrongdiagnosis.com/a/autosomal_recessive_genetic_diseases/intro.htm
Same thing as above, but this time the diseases are caused by having
two copies of the recessive allele - thalassemia and cystic fibrosis
are the most well-known.

If you're looking for non-disease traits, here's a nice PDF table from
the SDSC Science Enrichment Program:
http://education.sdsc.edu/enrich/downloadables/mendelian_traits.pdf


I found the above by doing a variety of Google searches, as follows:
"dominant genetic traits humans"
"dominant genetic diseases humans"
"recessive genetic diseases humans"

Please let me know if I can help further with this or other questions
(I love genetics!) -

Librariankt

The sites identified were very useful

Try blood type:

A dominant over O
B dominant over O
A and B co-dominant

pretty good explanation here:

http://gslc.genetics.utah.edu/units/basics/blood/types.cfm

some examples:

mom is AA, Dad is BB

child MUST be AB (codominant)

mom is AO, Dad is BO

child gets 1 from each parent.

therefore, all possible outcomes for the kid are:  AB, AO
[phenotypically A], OB [phenotypically B], OO [phenotypically O]

another decent explanation:

http://www.transweb.org/qa/qa_txp/faq_abo_alleles.html

Blood type is not an example of dominant-recessive inheritance in
humans. It is an example of co-dominance. Simple dominant-recessive
relationships are described as having two alleles at a single locus
where the presence of one allele will mask the presence of the other
allele.

Some good examples in humans include:

Free ear lobes are dominant over attached ear lobes.

Having a cleft chin is dominant over having a smooth chin.

Ability to taste PTC (Phenylthiocarbamide,a bitter chemical) is
dominant over the inability to taste PTC.

Tongue rolling is dominant over the inability to roll your tongue.