If y chromosomes are smaller and contain less DNA, is this deficiency in DNA reflected in total genomic DNA concentration between the male and female sexes?
Hello Divya
That small difference between DNA content of Y & X chromosome cannot be recognized from extracted DNA. Although as you may be aware of, PCR will help you to detect sex-specific genes from DNA.
Hi Ali,
Thanks for your response.
I asked the question based on a result I found where there was 3-4 fold differences in the extracted and quantified total genomic DNA concentration between fruit fly males and females.
I could find no reports of these measurements, no reports of cell count or anything that might be the reason for this difference.
Hello again
Good to know that. In fruit fly, because of lower number of chromosomes than most mammalian species, the relative difference between X or Y containing cells might be more pronounced. However, 3 to 4-fold difference is too much. First of all you need to be very precise in terms of amount of tissues/sample (0.000 accurate scale) for DNA extraction.
Regards,
AJ
The experiment was done using biological triplicates of pooled 5 male and 5 female heads, processed at the same time, in the same way. The flies were all of equal age. It is true, I have not measured each sample amount individually, but I assumed real differences would be apparent using triplicate samples.
The DNA extraction method is not from a kit- it was done using Tris-EDTA-SDS lysis buffer- as I was interested only in quantifying the DNA, without need for any down-stream processing. However, my results are consistent between the sexes. Hence the surprise and the confusion.
you might not need a difference in the dna itself. Some difference might be due to a difference in size of males/females , a difference in the amount of soft tissue between the genders and possibly even small differences in cell wall structure so that some cells lyse easier than others releasing more dna. On OD260/280 would also help as protein or rna in some extractions will look like dna if only absorbance at 260 is used to measure the amount of dna
Thank you Paul.
I measured A260/A280 from the nanodrop for the amount of DNA. I suppose the differences in the male/female head anatomy or cell wall structure is the best explanation I've got so far.
Of course, if there are any published reports of these differences I would be more than glad to hear of it!