Y-chromosomal DNA

Figure 5. Detection of male MSC by Y-PCR. Y chromosome PCR at 24 h after MSC infusion from a male donor into female recipients with AKl. The only organ positive for Y chromosome DNA was the lung (lane 2). Kidney cortex and medulla as well as liver and spleen from 2 animals were negative (lanes 3-11). Lane designation A-female DNA B-male DNA 2 lung 3-kidney cortex 4-kidney medulla 5-liver 6-spleen 7-wound scar 8-lung 9-bone marrow 10-liver 11-spleen.

In parallel to that, two other techniques are being utilized with specific objectives. They include mitochondrial DNA and Y chromosome DNA analysis. Mitochondrial DNA (mtDNA) is a double-stranded DNA... 

Wlaschek M, Angulewitsch A, Bunemann H (1988) Structure and function of Y chromosomal DNA I. Sequence organization and localization of four families of repetitive DNA on the Y chromosome of Drosophila hydei. Chromosoma 96 145 - 158... 

Chromosomal aberrations Gene mutation Dominant lethal mutation Micronucleus formation Micronucleus formation Micronucleus formation Chromosomal aberrations Sister chromatid exchange Micronucleus formation Chromosomal aberrations Sister chromatid exchange DNA-protein cross-links Nondisjunction of Y chromosome in sperm DNA damage (single-strand breaks)... 

Detection of chromosome fragments. Individuals with Turner s syndrome are, in some cases, mosaic for a portion of or for the entire Y chromosome (46,XY/45,X). Since such individuals may be at increased risk for gonadal tumors, Southern blot or PCR analysis has been used to detect the presence of Y chromosome segments in studies of DNA from peripheral blood samples. Similarly, the fetal sex as well as the presence of some aneuploid states (e.g., trisomy 18) can be determined by analysis of DNA from chorionic villi or amniotic fluid cells. 

Answer E. The 3 to 5 exonuclease activity of DNA pol 8 represents the proofreading activity of an enzyme required for the replication of human chromosomal DNA. DNA pol y (mitochondrial) and DNA pol III (prokaryotic) do not participate in this process, short RNA primers are replaced with DNA during replication, and new DNA strands are always... 

Normal males inherit an X chromosome from their mother and a Y chromosome from then-father, whereas normal females inherit an X chromosome from each parent. Because the Y chromosome carries only about 30 protein-coding genes and the X chromosome carries hundreds of protein-coding genes, a mechanism must exist to equalize the amount of protein encoded by X chromosomes in males and females. This mechanism, termed X inactivation, ocairs very early in the development of female embryos. When an X chromosome is inactivated, its DNA is not transcribed into mRNA, and it is visuahzed under the microscope as a highly condensed Barr body in the nuclei of interphase cells. X inactivation has several important characteristics It is random—in some cells of the female embryo, the X chromosome inherited from the father is inactivated, and in others the X chromosome inherited from the mother is inactivated. Like coin tossing, this is a random process. 

In the particular case of geographical spreading of single locus mutations on mitochondrial DNA or on Y chromosome [22, 23], we consider a growing population that diffuses slowly in time and assume that the net rate of growth is a linear function of population density, p(n) = — njrioo), where is... 

The human genome contains approximately 100000 genes which are distributed with a total DNA sequence of 3 billion nucleotides. The DNA of the human genome is divided into 24 exceptionally large molecules each of which is a constituent of a particular chromosome, of which 22 are autosomes and two are sex chromosomes (X and Y chromosomes). 

Right The human karyotype/ a full set of chromosomes numbered according to size and content and showing characteristic banding patterns. The 22 autosomes plus either an X or Y chromosome make up the haploid set which, for the female, contains - 3,500 Mbp of DNA. Each diploid cell contains 46 chromosomes. From Alberts et at. 

DNA analysis has also been useful in tracing human migration.337 3386 For example, a genetic marker in the Y chromosome is carried by 85% of native Americans, suggesting that they are all descended from a man who lived -20,000 years ago, probably an immigrant from Siberia 339 Contrary to usual assumptions women, more often than men, seem to have spread their DNA to new locations in the world.327b Studies of cattle and of the wild ox reveal information about domestification of these animals about 10,000 years ago in Europe, Asia, and Africa.340... 

In cases when a sample yields particularly well-preserved DNA, molecular sex determination can be performed by screening a portion of the amelogenin gene that exhibits a 6 bp deletion on the X-chromosome relative to its homologue on the Y-chromosome (53).7 The primers for this PCR reaction are found in Table I. Set-up the PCR as just described and run the reaction for 60 cycles. The use of an additional 20 cycles (40 cycles are typically used to amplify mtDNA) helps compensate for the feet that only one pair of sex chromosomes are present in each cell. 

A B / Hybridization detected V y in B chromosomal DNA implying that the DNA probe is specific for the B chromosomal fraction. 

FIGURE 9.5 Sex determination from human genomic DNA using the PCR-CE microdevice. Top amplification from female DNA. Only the 157 bp peak representing amplification from the X chromosome is seen. Middle amplification from male DNA both the 157 bp X-chromosome and the 200 bp Y chromosome amplicons are observed. Bottom DNA sizing ladder for amplicon size reference, run separately on the same device [282]. Reprinted with permission from the Royal Society of Chemistry. 

DNA polymerases a and 8 replicate chromosomal DNA, DNA polymerases (3 and e repair DNA, and DNA polymerase y replicates mitochondrial DNA. 

Eukaryotic cells contain five different DNA polymerases a, (3, y, 8 and e. The DNA polymerases involved in replication of chromosomal DNA are a and 8. DNA polymerases (8 and e are involved in DNA repair. All of these polymerases except DNA polymerase y are located in the nucleus DNA polymerase y is found in mitochondria and replicates mitochondrial DNA. 

Yoshikawa, T., F. Nakanishi, Y. Ogura, D. Oi, T. Omasa, Y. Katakura, M. Kishimoto, and K. Suga. 2000. Amplified gene location in chromosomal DNA affected recombinant protein production and stability of amplified genes. Biotechnol Prog 16 710-715. 

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