DNA applications in cell-line individualisation
In-vitro propagation of human cells has developed drastically over the years and it has been proven to be an outstanding technical advance; which has applications in various phases of human biology. However, this technology’s history has become sort of ‘tainted’. This is due to the fact that an inception via an incidence; which is mistaken cell identity, therefore causing incorrect conclusions because of the contamination of cells. The most aggressive cell line, HeLa cell line, which is cervical carcinoma cell line, has been found to be the most common contaminant.
In 1967, frequent cell mix up was firstly suggested. During that process, a total of eighteen human cell structures had gone under testing for Isozyme marker. Most of the cells lines were taken from Caucasian people as testing from Blacks was not restricted. The results were strange as it seemed like each one has been taken over by a very aggressive human Tumor line, which was the HeLa. The conclusion of these experiments confirmed that when a commonly one of a kind Chromosome translocation or the markers, was found in each of the suspect cell lines were in fact exactly identical to the one described originally in the culture of the HeLa. More than ninety HeLa cells contaminations were discovered over the course of a decade. Those HeLa contaminations were being developed for researches regarding cancer as well as cell biology. This resulted in much financial loss, and many hours of research and energy spent.
As gene cloning began to advance, a considerable number of genetically hypervariable regions were discovered in the Human DNA. Those regions are usually related to gene families. They are often dispersed to different human chromosomes. Their composition is of tandem repeats of sequences; short core ones, which show abundance within the variations of the repeated units numbers. A set of DNA probes caused of those tandem repetitions produce a fingerprint. Hybridisation to genomic DNA is able to identify several Hypervariable loci; which makes a fingerprint. The germline stability can be shown via the DNA fingerprint. The being successfully applied in many fields: forensic medicine, animal populations and the preliminary reports regarding cell analysis. A certain level of polymorphism has been detected by the probes, which gave an allowance of individualisation of cell lines to be tested in an unambiguous manner. The implications of HeLa derivatives have been included in this analysis; nine cell lines all of which are derivatives.
The amount of genetic differences between individuals is quantified based on a parameter; it’s called APD or ‘average percent difference’. Fragment frequency of a DNA was found to be related to ‘allele frequency’ at ‘multiple (N 10) homologous genetic loci. This was done based on a genetic Model. This model made the estimation of the probability of any specific DNA fingerprint possible.
Applying these methods to a population of a culture of human cells, gives measures of a cell line individuality that is robust as well as straightforward.