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RELATIONSHIP BETWEEN HEREDITY AND DNA 1. DNA Polymerase Not Perfected by Evolution What are passed on by parents to their children are sets of genes in the chromosomes and these interact with the environment where they are found (Genetic Science Learning Center, 2005). Given the proper environmental conditions, the genes can be expressed fully in an organism. Offspring's do not inherit a trait but the genes that control the appearance of that trait. Genes can be fully expressed if the proper environment is provided. Genes, therefore, can determine what an organism may become.
The organism is a product of the interaction of the genes and the environment. Hence, one of the ways DNA are mutated is through the environmental factors which damage DNA leading to cell making mistakes in copying its DNA prior to division (Genetic Science Learning Center, 2005). This interaction with the environment has kept DNA polymerase from being completely without mistakes. 2. Germline Gene Therapy The modification of a germline gene has caught heated debates between its proponents who are persuaded due to the promise of eliminating bad genes and those who oppose the mere manipulation of genomes, as it is unethical. The debate boils down to two issues- the significant contribution of germline modification in preventing diseases on the one hand, and the ethical issues hounding the modification or alteration of genomes (q. in Gilbert, 1997).
According to Gilbert (1997), Wivel and Walters germline gene modifications would be justified in cases when the parents are infected with disorders or diseases certainly to be inherited by their offspring's. Basically, these justifications are best summed up in looking at germline gene therapy as the duty of the physicians in using the best possible methods in ensuring the health of their patients and in considering that parents have the right to afford to their children the best possible treatment and health protection (q. in Gilbert, 1997). Setting aside ethical issues, Wivel and Walters identified arguments against the use of the germline gene therapy as it has yet to prove its worth as regards risks involved (q. Gilbert, 1997).
Further, the two give the argument that there are other effective alternative strategies in addressing genetic disorders or diseases and that germline gene method has limited applicability despite its being costly (q. in Gilbert, 1997). It could be gleaned from the medical fact that this method, as aptly contrasted by Bruce (n. d. ) from somatic gene therapy such that if the latter is considered as in its infancy stage, the former is not even a twinkle in the parents eyes. This only emphasizes that since germline gene therapy has only been applied to animals, the risks involved would be huge if applied to humans because of the fact that it has yet to be tested with humans. Setting aside the are we playing God issue as this would lead to a chicken and egg question, some scientists have noted the alterations that modification at the germline level would have in society.
For one, they believe that this would only worsen the discrimination and gap between the rich and the poor considering the costs that people have to shell out in order to afford the said method (Deep, at. al. , n. d. ). Further, the method could be socially damaging as it might reinforce the stereotypes concerning what is and what is not normal (Deep, et. al. , n. d. ).
In essence, the germline debate is not just constrained in the limited issues of whether it could be done but also concerns itself as to whether it should be done considering the ethical questions raised by its opponents and the fears of social damage put forward by some scientists. 3. Different Types of Cells When the male and female gametes meet, a fertilized egg is formed which undergoes cell division as it moves along the fallopian tube until it reaches into the uterus as tiny, many celled embryo. The cells in the embryo all look the same but these cells forming the different organs differentiate at a particular time in the proper order. This period where changes in an unspecialized cell to become specialized into one of the cells that will make up the body such as its organs is called cell differentiation (q. in Ewoldsen). Of the cells of multicellular organisms, differences in composition, structure, and function that arise through selective gene expression.
According to Starr and Taggart, all the cells inherit the same genes but become specialized by activating or suppressing some fraction of those genes in different ways (q. in Ewoldsen, n. d. ). 4. Special Type of Cell Division in Sexual Reproduction Based on the studies made by scientists, new individuals always have the same number of chromosomes characteristics of their species. In the unity of the egg cell and the sperm cell with each having the same number of chromosomes, which is 26, remains normally the same as the number of chromosomes does not add up as new zygotes are formed (Farabee, 2001).
As the number of chromosomes does not double or triple, this suggests that a different kind of cell division must take place in an individual in order to reduce the number of chromosomes in half. This kind of cell division is called meiosis. In reducing the number of chromosomes in half when fertilization occurs, the number of the sets of chromosomes of the parents is retained resulting to offspring looking basically like their parents and other members of their species (Farabee, 2001). Without meiosis, the offspring formed may not look like humans as the number of chromosomes doubles or triples. REFERENCES Bruce, Donald M. Moral and Ethical Issues in Gene Therapy.
Accessed 16 July 2006 at: < web >. Deep, Alex, Teresa Plant, Asher Louden, Nabarun Dasgupta, and Filip Bear. Germline Gene Therapy. Accessed 16 July 2006 at: < web courses / mb 427 / 2000 /projects/ 0007 /index. htm>. Ewoldsen, Mark.
Asexual and Sexual Reproduction Notes. Accessed 16 July 2006 at: < web > Farabee, M. J. Cell Division: Meiosis and Sexual Reproduction. On-Line Biology Book 21 June 2001. Accessed 16 July 2006 at: < web BIOBK/BioBookmeiosis.
html>. DNA and Molecular Genetics. On-Line Biology Book 20 June 2001. Accessed 16 July 2006 at: < web BioBookDNAMOLGEN.
html>. Genetic Science Learning Center. How Do Mutations Occur? Genetic Disorder Corner. The University of Utah: 2005. Accessed 16 July 2006 at: < web >.
Gilbert, Scott. Genes and Development. 07 February 1997. Accessed 16 July 2006 at: < web >
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Research essay sample on Gene Therapy Sexual Reproduction
