DNA Qs: XY, XX, mitochondrial ....?
So like I hear that the Y chromosome is only transmitted through males. True?
Also heard that mitochondrial DNA is only transmitted through women. True?
Does the Y chromosome have less genetic info?
Ummm.... that's it for now. I'm just curious.
Update:If Y chromosome has fewer genes does that mean all males have fewer genes? (I thought all people had like 23,000 genes)?
Am I less human?
Comments
Only men carry the Y-chromosome. Therefore, the Y-chromosome is only transmitted through men.
mtDNA is not carried by sperm cells, but it is carried by egg cells. Therefore, mtDNA is transmitted by the female only.
The Y-chromosome is shorter than the X-chromosome. It has fewer genes, leading to sex-linked factors. Examples are red/green colour blindness, and haemophilia.
Men inherit an X chromosome, which bears genes impacting both sexes, as well as the Y chromosome with additional information. The Y genes control some of the differences between the sexes. One of these even alters a ribosomal component. This means every ribosome in a male is slightly different from a females. Given the potential of the Y genes there seems to be a 1-2% difference in the genomes of men & women.
'The Y Chromosome: Men Really Are Different'
http://txtwriter.com/Onscience/Articles/ychromosom...
There is the MSY, for 'male-specific region of the Y, a distinct region with functions that determine slightly different paths during development. These are the genes that modify the basic information for the male developmental process to be completed. They are what create testis rather than ovaries as well as several genes important in spermatogenesis, the TSPY (testis-specific protein). In total there are fewer than 90 coding genes identified so far but there are potentially more not yet identified. The Y chromosome has been the most difficult to sequence and analyze due to numerous palindromic repeats.
Chromosome X has has between 900 and 1,400 genes. These provide information in men as well as in women. In fact women only have one X chromosome active keeping the sexes comparable in development. The second X becomes a barr body and is inactive.
http://users.rcn.com/jkimball.ma.ultranet/BiologyP...
The allosomes are the only chromosomes that can appear in various numbers with little developmental problems. They seem to function with extra copies or missing copies. Turner's syndrome is XO while Kleinfelter's is XXY but people have lived with XXXY.
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC204015...