Type dominant, space, recessive, into google.
Teach Christina how to copy and paste.
Then she can copy the URLs below and paste them into
the browser.

Go to
http://library.thinkquest.org/C0125833/english/dominant.php
Then "proceed to Human Genome - The Blueprint of Humanity" click here
The "Dominant/Recessive Genes" discussion is pretty good.

Master is on PC at home.

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An interesting recessive trait:  "blueness"
http://www.people.virginia.edu/~rjh9u/day3.html
and
http://www.people.virginia.edu/~rjh9u/blkysc82.html

http://en.wikipedia.org/wiki/Methemoglobinemia

Martin Fugate was a French orphan who emigrated to Kentucky in 1820 to claim a land grant on the wilderness banks of Troublesome Creek. 
No mention of his skin color is made in the early histories of the area, but family lore has it that Martin himself was blue. 

The odds against it were incalculable, but Martin Fugate managed to find and marry a woman who carried the same recessive gene. 
Elizabeth Smith, apparently, was as pale-skinned as the mountain laurel that blooms every spring around the creek hollows. 

Martin and Elizabeth set up housekeeping on the banks of Troublesome and began a family. Of their seven children, four were reported to be blue. 



                With only a few exceptions, every cell of
                the body contains a full set of
                chromosomes and identical genes. Only a
                fraction of these genes are turned on,
                however, and it is the subset that is
                "expressed" that confers unique
                properties to each cell type. "Gene
                expression" is the term used to describe
                the transcription of the information
                contained within the DNA--the repository
                of genetic information--into messenger
                RNA (mRNA) molecules that are then
                translated into the proteins that perform
                most of the critical functions of cells.
                Scientists study the kinds and amounts of
                mRNA produced by a cell to learn which
                genes are expressed, which in turn
                provides insights into how the cell
                responds to its changing needs. Gene
                expression is a highly complex and tightly
                regulated process that allows a cell to
                respond dynamically both to
                environmental stimuli and to its own changing needs.
                This mechanism acts as both an "on/off" switch to
                control which genes are expressed in a cell as well as a
                "volume control" that increases or decreases the level
                of expression of particular genes as necessary.