Posted by:
Lamapunk
at Fri Jul 25 02:43:09 2008 [ Email Message ] [ Show All Posts by Lamapunk ]
This is the part that is really getting me:
Symbols
Some of the names that are used to describe various color and pattern mutations are rather long. For example, the name “Lavender albino” contains 14 letters. Using the entire word when filling in a Punnett Square would make for an enormous Punnett Square. Abbreviations of the names are used instead of the entire name describing the mutation. Mendel originated some of the rules used for symbolizing today.
1. The symbol is a unique one to four letter abbreviation of the mutant name. For example, a could be used for albino. As a is already taken, ax could be used for axanthic.
2. All characters in a recessive mutant’s symbol are lower case. Again, a is for albino, a recessive mutation.
3. All characters in a dominant or codominant mutant’s symbol are lower case, except for the first letter, which is upper case. For example, Ti could stand for tiger, a codominant mutant in the reticulated python.
4. The symbol of the locus is the same as the symbol for the first mutant gene found at that locus. For example, a stands for both the albino mutant gene and the albino’s locus. Ti stands for both the tiger mutant gene and the tiger’s locus.
5. The symbol of the wild type or normal allele at each locus is the locus symbol followed by a plus sign as a superscript. For example, the wild type allele at the a locus would be a . The wild type allele at the Ti locus would be Ti . If usage is clear, the wild type allele can be symbolized by a plus sign alone.
6. As genes come in pairs, there are two alleles in a genotype. The two symbols may be separated by two slash marks (//), particularly in complicated genotypes. While useful, the slash marks are optional. For example, an albino individual could be symbolized either a//a or aa. A heterozygous tiger could be either Ti//Ti or TiTi .
7. The more dominant allele goes on the left side of the genotype and the more recessive allele goes on the right side of the genotype.
Always remember to clearly label all the symbols used in your Punnett Squares.
I just cant grasp it and it seems like I should be with no prob...in turn its making me feel a little...not smart.
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RE: punnet squares and genetic terms - Lamapunk, Fri Jul 25 02:43:09 2008
