There are different cell potencies. A <u>totipotent</u> cell is a stem cell that can divide itself and <u>differentiate in any cell </u>that the organism needs. That is to say, endodermal cells, ectodermal cells, mesodermal cells, or extra-embryonic tissues. As cells differentiate themselves, they can gradually lose their potential. The cell's category that follows is pluripotent cells. These are stem cells that can only differentiate into ectoderm cells, endoderm cells, or mesoderm cells. Then we have multipotent cells, which differentiate into tissue cells. The next category is oligopotent cells. They give a limited number of specific cells, and lastly unipotent cells, only differentiate in one type of cell.
Alleles that are recessive will be lower case. Alleles that are dominant are upper case. Since we have two recessive alleles represented by 'R', the alleles would be written as 'rr'.
