Overall the idea that genes are seperate entities on a beaded string is valid simplication for Mendelian genetics.Quote:
Originally Posted by JLC
However, I would add some things to your model
For one there is more than one string of beads. For example, humans have 46 chromosomes. What this means is we actually have 46 DNA molecules. Each chromosome contains one DNA molecule plus packaging material. Each DNA molecule contains segements that code for proteins of specific function. We call these segments genes.
In your analogy, if albino and pastel follow a classic Mendelian mode of inheritance than the gene for pastel and albino are different beads on different strings! In other words, the gene for pastel resides on a different DNA molecule or chromosome than the gene for albino.
It is possible that the gene for pastel and albino are on the same chromosome. We call genes on the same chromosome linked genes. If genes are linked than the typical two gene trait probabilties are not valid.
This is because linked genes do not follow Mendel's law of independant assortment. For two linked recessive traits, for example, your chances of producing a double recessive from the breeding of two double hets would be much better than the typical 1 in 16 chance....it would be much higher and closer to 1 in 4!
To determine if a gene is linked through breeding experiments alone would be difficult in an organism like the ball python which has small number of offspring.