Investigate the use of technologies to determine inheritance patterns in a population using, for example: DNA sequencing and profiling

In a time when genetics is dramatically impacting human biology and medicine several techniques and information having provided us data for the study of genetic disease risks and treatments. The Sanger Method was the standard sequencing technology for over three decades and was based on the DNA chain termination via a concentration of radio or a fluorescent dNTPs which were then separated by gel electrophoresis (Maxam & Gilbert, 1977). Following after came the high throughput-next generation sequencers (HT-NGS) which included the second generation technology and the third generation technology. The second generation sequencing technologies or NGS included the SOLiD (Applied Biosystems for Life Technologies), Illumina/Solexa and Complete Genomics.
The third generation sequencing technology is known for its lack of DNA or RNA amplification in template library preparation; in other words single molecular sequencing. The third generation of HT-NGS were capable of producing approximately five hundred basis of raw sequence and some could up to billions in one run. The third generation sequencing is known for its less requirement of genomic DNA, avoiding PCR errors, amplification biasness and superiority in terms of high-throughput sequencing application (Dewey, Pan, Wheeler, Quake & Ashley, 2012). The third generation sequencing include the Heliscope single molecule sequencer, single molecule real time sequencer (SMRT), single molecule real time sequencer (RNAP), nanopore DNA sequencer, real time single molecule DNA sequencer platforms developed by VisiGen Biotechnologies, multiplex colony technology and ion torrent sequencing technology.
DNA sequencing has provided with much information that can not only help us form the Human Genome Project but discover newer reasons for diseases, make personalized medicine and also in DNA profiling. The focus of this essay will be DNA fingerprinting. Genetic identity testing is usually done by identifying a unique patter that is unique to the one individual and therefore can act as a distinguishing pattern (Cooper, Smith, Cooke, Niemann & Genet, 1985). These sequences or pattern are used for identity testing and involve various technique such as the DNA fingerprinting, DNA profiling and DNA typing, though all three are used interchangeably (Saad, 2005).
The first ever case of a DNA profiling as a problem solving tool was when a family from Ghana visited the UK and attained their citizenship. Due to a complication in finding out if the son really belonged to family Professor Jeffreys help was taken who sampled the DNA from the mother’s other children and tested against the supposed son. The results came out positive and thus, this case opened the door for using DNA fingerprinting in DNA profiling (Jeffreys, Brookfield & Semoneoff, 1985).
In 1986, Jeffreys received a call to solve another murder case when he felt that the old technique would not work since the case required a large amount of DNA, therefore, he used a probe that had sequences attached to different minisatellites loci. To simplify the assay a single locus probe recognizing at most two DNA segments in an individual (corresponding to two alleles); one from the mother and the other from the father. Towards the end of `1986 DNA profiling had been established for use and being refined by the introducing of PCR and different repeating sequences called microsatellites (Tautz, 1993) Amplification by PCR provided an increasing sensitivity which allowed smaller amounts of DNA to be analyzed regardless of whether they were archived or partially degraded. The minisatellites were made up of repeated sequences that could vary in unit length from six to hundred bases (Weber, 1990). Microsatellites on the other hand were repeating units that came about five to hundred times at each microsatellite locus (Weber, 1990; Koreth, O’Leary, O’D McGee & J Pathol, 1996). In 1994, Federa Bureau of Investigation expanded a pilot project to launch the DNA database project; the Combined DNA Index System (CODIS). CODIS was a tool made to fight against crimes and combined DNA analysis with computer technology whereby which forensic labs around the country could share information about DNA profiles electronically (McEwen, 1995).
The first DNA typing technology was the RFLP or restriction fragment polymorphism, which involved core units of sequences of about 30 to 100 nucleotides present in repeats. This method required a large amount of DNA which wasn’t feasible when solving murders. Then STR, or short tandem repeats typing was introduced and is currently being used. For this method the loci is composed of eighty to four hundred base pairs which are co-amplified. The automated DNA fragment analyses helps the results to be obtained on the same day itself and also requires lesser amount of DNA sample (Panneerchelvam & Norazmi, 2003).
Use of genetic testing has brought up several ethical dilemmas which had to be addressed. Such as autonomous agents and their choices required to be respected. In the context of genetic testing and screening, respect for autonomy referred to the right of the person to make an informed. Independent judgement regarding whether they wished to be tested or not. If, yes, then they should also be provided with the results of the test. The tested has the right to choose his or her destiny without interference from a genetic report. The autonomy also provides the DNA provider the right to control the use of its genetic material regardless of past, present and future. In some cases though genetic testing has been made compulsory thereby which a person’s autonomy is automatically over-ruled by law to prevent harm. Example: to screen a new born for phenylketonuria. Rules of confidentiality exist which prohibit a physician from disclosing personal information to an insurance company or an employer without the patients consent. In terms of privacy, once a person undergoes genetic testing, the tested has the right to be informed and choose to select authorities who may know about their genome. In terms of equity, there is a concern that genetic disorders or predispositions might bar some people from being provided access to certain social goods such as employment and health insurance. (Andrews, Fullarton, Holtzman & Moltusky; Assessing Genetic Risks: Implications for Health and Social Policy, 1994).
When discussing population data for DNA profiling it is understood that due to the limited time there entire genome of a person cannot be sequenced. It must be remembered that DNA typing is only a type of examination whereby which sample of DNA is sequenced at discrete locations. To determine if a genotype is to occur in a population, a population data is compiled to make an estimate of the frequency of alleles and genotypes. The database is compiled based on ethnicity or racial groups and sub-visions are not included due to their being even greater genetic variation from the larger groups. The current method in use is considered too conservative to compensate for small sub-group variations. Therefore in 1992, the NRC recommended that the ceiling principle for making adjustment to population sub-divisions. Also, the NRC also allowed the use of DNA in court only after standardized proficiency tests and accreditation. Later in 1996 the NRC also approved the methods for DNA typing and statistical interpretation to be accepted if properly collected. The NRC also recognized that the uniqueness of DNA typing cannot be achieved unless all the population data is typed. The report further required that a high degree of confidentiality about the source of DNA should be maintained whereby which the FBI determined a threshold value under which DNA profiling could be done (Panneerchelvam & Norazmi, 2003).
Genetic sequencing and profiling has also opened up new gateways of research whereby which DNA manipulation has become possible. Genetic engineering is the term used for alteration of an organism’s genetic material to either eliminate undesirable trait or to add a desirable one. Major focus of this has been on crops, animal food production, vaccines and pharmaceutical drugs. Method used could be selective breeding for animal and plant crops, hybridization (cross mating species) and/or recombinant DNA technology. Although there are many positive aspects of this, but there are some ethical concerns. It is difficult to predict the changes that genetic engineering can bring upon the environment. Releasing genetically modified organisms into the open could create an imbalance in the ecology (Mercer, Scott, Bruce-Johnson, Glover & Flint, 1999). One fear is that any modification could produce a new and better strain of a virus or another microbe which could cause a serious epidemic. There also has been a concern that antibiotic resistance genes in food could result in stronger bacteria or fungi to be engineered which could have lethal effects In terms of effects on human beings, the use of virus vectors for carrying functional genes is being studied extensively and its true repercussions are still unknown. There is little to no result being obtained as to whether these functional genes are being placed or not. There is also a concern that as defective genes are replaced by the functional ones, gene pool may decrease and might result in a large number of population having identical genome. Certain changes in animal or plants may result in an allergic reaction which would not occur if used in its original form (Jr FW, 1996).
Maxam, A.M., Gilbert, W., (1977). A new method for sequencing DNA. Proc Natl Acad Sci U S A. 74(2). 560–564. Retrieved from:
Dewey, F.E., Pan, S., Wheeler, M.T., Quake, S.R., Ashley, E. A., (2012). DNA sequencing: Clinical applications of new DNA sequencing technologies. Circulation. 125(7). 931-944. Doi: 10.1161/CIRCULATIONAHA.110.972828
Cooper, D.N., Smith, B.A., Cooke, H.J., Niemann, S., Schmidtke, J., (1985). An estimate of unique DNA sequence heterozygosity in the human genome. Hum Genet. 69(3). 201–205 retrieved from:
Saad, R (2005). Discovery, development, and current applications of DNA identity testing. Proc Bayl Univ Med Cent. 18(2). 130-133. Retrieved from:
Jeffreys, A.J., Brookfield, J.F., Semeonoff, R. (1985). Positive identification of an immigration test-case using human DNA fingerprints. Nature. 317(6040. 818–819. Retrieved from:
Tautz, D., (1993) Notes on the definition and nomenclature of tandemly repetitive DNA sequences. EXS. 67. 21-8. Retrieved from:
Weber, J.L., (1990) Human DNA polymorphisms and methods of analysis. Curr Opin Biotechnol. 1(2). 166-171. Retrieved from:
Koreth J, O’Leary, J.J., O’DMcGee, J., (1996) Microsatellites and PCR genomic analysis. J Pathol. 178(3). 239-248. Retrieved from:
McEwen, J.E., (1995). Forensic DNA data banking by state crime laboratories. Am J Hum Genet. 56(6). 1487-92. Retrieved from:
Panneerchelvam. S., Norazmi, M.N., (2003) Forensic DNA Profiling and Database. Malays J Med Sci. 10(2). 20-26. Retrieved from:
Andrews, L.B., Fullarton, J.E., Holtzman, N.A., Motulsky, A.G., (1994). Assessing Genetic Risks: Implications for Health and Social Policy. Washington (DC): National Academies Press (US).
Mercer, D.K., Scott, K.P., Bruce-Johnson, W.A., Glover, L.A., Flint, H.J. (1999) Fate of free DNA and transformation of the oral bacterium Streptococcus gordonii DL1 by plasmid DNA in human saliva. Appl Environ Microbiol. 65(1). 6-10. Retrieved from:

Jr FW (1996) Viral Genetics. In: Medical Microbiology. 4th Edition edn. University of Texas Medical Branch at Galveston. Retrieved from:

Leave a Comment

Your email address will not be published. Required fields are marked *