MadSci Network: Genetics |
Hi Azad, the reason why the chromosomes are called homologous is because they are (very) similar to each other - at least from a remote point of view. However, as you know, half of the genetic information originates from the mother, the other half originates from the father. However, this genomic information from father and mother is shuffeled during genetic recombination. Therefore alone can the order of nucleotides in the human chromosomes not be the same in all humans, not even sisters or brothers having the same parents. Even in identical (i.e. monozygotic) twins the exact order of nucleotides is not identical. This is brought about by numerous mutations that occur all the time, everyday and everywhere. As such, every individual will differ et least slightly from another and there is no exact "order of nucleotides" for any species on this planet. Keep in mind that genome sequencing projects only give a snap shot of the genome of a mixture of a couple individuals. Hope that helps.
Try the links in the MadSci Library for more information on Genetics.