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When it produces sperm or egg, the chromosomes are split in a few places. This event is known as a crossover. The result is that loci on chromosome 1 from mom can be mixed with other loci on chromosome 1 from dad. The results can be chromosomes that look something like this: . a b c D E F G . . H I J k l m . Sperm/egg cell 1 . A B C d e f g . . h i j K L M . Sperm/egg cell 2 Notice that instead of all sperm cells carrying either "cd" or "CD" some of them can carry "cD" or "Cd." These crossovers take place between a few random loci for each sperm/egg cell. The amount of linkage can vary based on the physical distance between the loci on the chromosome. With a strong linkage, the two loci will almost always be inherited together from the same parent. This can have the effect of making it virtually impossible to combine two recessive traits into the same individual, or virtually impossible to separate two traits that are inherited from the same parent. For example, let's see what would happen if the Amel and Anery loci were linked. (This is a hypothetical example. They are not really linked.) Let's pick a number and say they inherit together 90% of the time. We'll use these symbols: "A" for the normal allele on the Amel locus, "a" for the amel allele, "E" for the normal allele on the Anery locus, "e" for the anery allele. [Home] [Digital Editions] [CMG Genetics Tutorial] [Serpwidgets Genetics] [Links] [Contact] Cornsnake Morph Guide is a registered trademark of Charles Pritzel All content on this site is copyright © 2004-2012, Charles Pritzel |