Does the age of an individual affect the dna or the genetic material of his body? I mean, if we try to reconstruct the individual using its dna, what would be his age? Or is dna completely independent of that? Its said that the incidence of crossing over decreases with age and linkage increases! Does that make the dna unique for a particular age?
Sorry for asking too many questions..but i am too confused! Pls solve my queries and correct me if i am wrong!!
In a way, age (or time) does affect dna, although best seen on genetic or chromosomal level. Down- or upregulation of many genes depends on the developmental phase of the individual. Furthermore, telomers on the chromosomes grow shorter on most cells after each cell division – so many cells have lost their ability to divide on older individuals. Mutations accumulate over time, this is one reason why cancer becomes more prevalent during aging: due to multiple pro-cancer changes. On nucleotide level, dna keeps constantly changing a bit due to point mutations caused by chance and accelerated by many environmental factors.
If you try to reconstruct an individual from a dna of a single cell, the outcome would naturally depend on the cell in question – what mutations have happened, what genes have been shut down etc etc. Nobody can tell for sure what would the "age" of a clone or reconstruct be, but I assume the overall age is pretty much the "age" of the cell that was used. E.g. a cell that has spent almost all its potential would most likely cause the clone to be "old" right from birth, unless telomers were rebuilt and needed genes upregulated again and so forth. If you used a stem cell with a lot of potential to divide, maybe the outcome would be better. And there are many more aspects to consider I didn’t mention here, or that I’m not even aware of. This is all very theoretical on most parts anyway 🙂