Molecular biology of the gene

I.       Introduction

A.    What is molecular biology of the gene?

Molecular biology is a science that studies the molecular basis of activity in living cells. It involves the study of molecular elements and how they function in relation to replication, mutation, expression and many other biological processes (Peter, 2005). In other words, molecular biology creates an understanding of the interactions between RNA, DNA and protein biosynthesis. The gene is the basic molecular unit for heredity and contains RNA and DNA is unique chains that enable them hold the information to build cells, maintain the same and ensure that genetic information is passed on to their offspring (Clausen-Schaumann, et al, 2000). This knowledge of molecular activity is often useful in controlling biological processes with advancements in molecular biology techniques known to be driving breakthrough in medical science and other fields.

B.     History and research result

Interest in molecular biology started as early as the 1930s with the term molecular biology being coined in 1938 by Warren Weaver (Benham and Mielke, 2005). In this early stage, mechanisms relating to gene reproduction, expression and mutation remained largely unknown. Further discoveries would be made in the 1950s starting with the discovery of the discovery of the double helical structure of DNA by Francis Crick and James Watson (Russell, 2002). These discoveries promoted the understanding of genes and the coding sequences that generate different types of proteins in the living organism. By the 1970s, scientists were focusing on the discoveries made in the field to solve unresolved medical problems in an era dubbed the Molecular era (Benham and Mielke, 2005). The information on genetic composition would be used on bacteria and other pathogens with an aim to finding a way of eradicating them. Advancements in the field have seen scientists gain the ability to create much larger sequences. The successes in molecular biology have made it possible for practices such as cloning to be conducted with relative success. It is also expected that some of the persistent medical problems will finally be resolved through the application of molecular biology technologies.

II.                DNA

A.    Definition

DNA stands for Deoxyribonucleic acid and it is a nucleic acid that contains genetic information necessary for the building and the functioning of living organisms (Berg, 2002). The segments of DNA that carry this information are called genes. The DNA structure comprises of two long polymers and phosphate groups which are joined by ester bonds. The polymers consist of nucleotides comprised of sugar backbones. These strands are anti-parallel. The DNA cells themselves are mainly comprised of chromosomes which play a key role in the transmission of genetic information (Lee and Gutell, 2004). At the base of each of the sugars are four nucleobases whose sequence encodes the genetic information.

B.     Technology application

Technology utilizes knowledge of the DNA to solve some of the issues around the world. One of these technological applications include genetic engineering where man made DNA sequences are introduced into living organisms with an aim to solve some of the weaknesses in such organisms (Sheridan, 2011). For instance, genetic engineering is commonly used in the field of agriculture where drought resistant and disease resistant strains of agricultural products are produced. These genetic modifications are also commonly used in the field of medicine.

            Technology has also been used to introduce the knowledge of DNA in fighting crime. Forensic scientists obtain genetic information from blood, hair, skin and any other parts of the body and this information is recorded for further comparison with the DNA data collected from suspected perpetrators of the crimes (Sheridan, 2011). The DNA technology has been very instrumental in raising the rate at which serious crimes are resolved around the world. Having been first used in 1988 in the Enderby murder case, the forensic technology has become an integral part of law enforcement in most countries (Kolata, 2009). Other technologies include bio informatics and DNA nanotechnology; both of which have been a manifestation of advanced knowledge in the field of molecular biology.

C.    The replication of DNA

Replication of DNA enables cells to transfer genetic information to the offspring cells. For reproduction to be considered as complete there needs to be an accurate transfer of genetic information. The double stranded structure of the DNA provides the basis for the replication. In the initial stage of the replication process, the two strands are separated (Watson, 2007). Upon the separation, the DNA polymerase (an enzyme) produces a complementary DNA strand. The subsequent stages of the replication process sees the cells divide into two with the new cells having similar characteristics as the parent cell.

III.             RNA

A.    Structure

RNA stands for Ribonucleic Acid. RNA is made nucleotides (long chain of components) where each nucleotide comprises of a ribose sugar, a phosphate group and a nucleobase. The structure of the DNA and the RNA are similar save for two distinguishing factors: Firstly, whereas RNA contains ribose sugar, DNA contains deoxyribose; and secondly, the RNA nucleobase contain uracil while that of the DNA contains thymine (Benham and Mielke, 2005).

The RNA nucleotide contains ribose sugar and carbons. These carbons are numbered 1’-5’. The main carbon elements include Adenine, Cytosine, Uracil and Guanine (Berg, 2002). The phosphate groups tend to be negatively charged hence making RNA charged molecules (Benham and Mielke, 2005). The hydrogen bonds formed between cytosine and guanine; guanine and uracil; and adenine and uracil dictate the kind of genetic information contained with some combinations being generally uncharacteristic. 

Source: Benham and Mielke, 2005

B.     RNA type

1.      mRNA

mRNA stands for messenger RNA. They copy information from DNA during protein synthesis in forms of series of three word codes (Clark, 2005). Each of these codes specify certain amino acids. These RNA are single stranded with no base pairing. However, random coiling may be observed.   

2.      tRNA

Transfer RNA contains the codes that help in deciphering the information carried by the messenger RNA (Buehler, 2012). They act as carriers of amino acids in the protein synthesis process and this they do by using the information carried by the messenger RNA.

3.      rRNA

The ribosomal RNA are found in the ribosomes (Benham and Mielke, 2005). The bases of these RNA are complementary parts of the DNA from which they are produced. They also bind the transfer RNA and all other molecule needed for protein synthesis. 

C.    Effect

The RNA helps in the process of protein synthesis. The three types of RNA work together to encrypt the information contained in the DNA and uses it to organise the amino acids in the corresponding sequences (Peter, 2005). The DNA and the RNA therefore work in tandem to ensure that body parts are built to specification and that genetic information is passed around with utmost accuracy.

IV.             Gene technology

A.    Transcription

The transcription process can be described as one that deals with the transfer of information from the DNA to the ribosomes using the messenger RNA (Russell, 2002). This transfer of genetic information is crucial in the process of protein synthesis with the specification of amino acids coded in the RNA nucleotide sequences. During transcription, the RNA polymerase copies the codons of a gene into the messenger RNA.  The RNA copy is then decoded by pairing the messenger RNA to the transfer RNA with a specialized ribosome reading the RNA sequence (Peter, 2005). The information is then transmitted to the ribosomal RNA which then decodes the information and combines amino acids and other molecules to form the proteins needed as appropriate. The use of technology to interpret this can also be used by scientists to influence the features of given organisms. By understanding the codes for specific proteins, genetic scientists are able to influence the formation of desired proteins that could see the organisms modified completely (Sheridan, 2011). Numerous scientific experiments are underway with the focus mainly being on developing disease resistant and highly productive strains of organisms.

B.     Gene diagnosis

Gene diagnosis involves the examination of DNA molecules with an aim to establish the vulnerability of patients to certain health conditions.  Gene diagnosis can be used in a number of situations including forensic/ identity testing, determination of vulnerability to cancers and other chronic diseases, determination of ancestry, newborn screening, pre-implantation screening and others (berg, 2002). This technology is hailed as one of the medical procedures with the lowest amount of risk. This is especially the case where the sample required is a blood sample, nail cutting, a strand of hair and others. However, prenatal testing heightens the risk of a miscarriage (Darden and Tabery, 2009). The advancement of this technology is a leap forward in the field of medicine with many individuals being able to predetermine their vulnerabilities and take pre-emptive measures to either prevent certain ailments or control them effectively.   

C.    Gene therapy

Gene therapy uses the DNA as a pharmaceutical agent to help in treating ailments. This therapy can be done by using the technologies related to molecular biology to alter individuals’ DNAs with an aim to either supplement or alter genes (Benham and Mielke, 2005). The new genes or combinations of the same then become more resistant to disease or health condition. The gene therapy approach is believed to be crucial in the treating of cancerous conditions where new body cells can be generated to replace those that have been mutated (Watson, 2007). The gene therapy involves a highly sophisticated process that involves the extraction of DNA information from the body and transferring it into the cell machinery. Once the information is secured, production of proteins begins.

Gene therapy can either be somatic or germ line. The somatic gene therapy involves the injection of the therapeutic cells into the body of the patient (Berg, 2002). These modifications are not hereditary and only impact the current patient. The germ line therapy affects the germ cells and involves the introduction of functional genes into the germ cells. This approach is hailed by specialized as having the potential to secure future generations by ensuring that they are free of some of the common health conditions (Sheridan, 2011). However, this type of therapy is largely frowned upon with most jurisdictions around the world prohibiting them. 

D.    Cloning

Cloning refers to the production of organisms that are identical to the parent ones. Cloning makes use of DNA collected from a single living cell and generates a large population of cells with identical DNA formations (Clark, 2005). The cloning process begins with the harvesting of cells from the desired organism. Such cells are then treated with enzymes in test tubes to generate smaller DNA fragments. The DNA molecules are then fragmented and recombined to yield similar cells as the original ones. When such cells are injected back into the body, the organisms become transgenic and will commonly be referred to as Genetically Modified Organisms (Clark, 2005). Cloning has had its mark in the agricultural sector where genetically modified organisms have been flooding the markets. Crops that can perform better in adverse conditions are being developed steadily. Cloning can also be applied to the regeneration of body tissues with further advancements proposed to even clone complete human beings (Sheridan, 2011). Cloning remains a thorny issue with societies around the world strongly opposed to the cloning of human beings. However, cloning continues to be a success in agriculture and medical fields.

V.    Conclusion

Advancements in molecular biology have seen the world benefit greatly from DNA and gene technologies. Having been started in the 1930s, this field of science has undergone rapid developments with greater discoveries made on the structure of the living organisms and how genetic information is transmitted from generation to generation. These sophisticated studies have been able to even unravel the nucleotide sequences in the DNA that result in the formation of certain kinds of proteins. As a result, scientists are able to influence the production of certain proteins through gene technologies. Major breakthroughs in the field of medicine and agriculture have in the past been attributed to the advancements in molecular biology. There has however been concerns raised on the extent to which molecular biology can be pushed with practices such as cloning of organisms raising high levels of attention around the world. In conclusion, molecular biology has given rise to unprecedented opportunities and relief to societies around the world.

References

Benham, C., Mielke, S., 2005. DNA mechanics. Annual Review of Biomedical Engeneering, 7, pp. 21–53

Berg, J., 2002. Biochemistry. New York: W.H. Freeman

Buehler, L.K., 2012. Molecular biology of the gene. (Online) Available at: http://www.whatislife.com/principles/principles13-molecular-biology.htm (Accessed 13 April 2012)

Clark, D., 2005. Molecular biology. Amsterdam Boston: Elsevier Academic Press.

Clausen-Schaumann,  H., Rief, M., Tolksdorf, C., Gaub, H., 2000. Mechanical stability of single DNA molecules. Biophysics Journal, 78(4), pp. 190-277

Darden, L., Tabery, J., 2009. Molecular biology. (Online) Available at: http://plato.stanford.edu/entries/molecular-biology/#1 (Accessed 13 April 2012)

Kolata, G., 2009. After Setbacks, Small Successes for Gene Therapy. The New York Times

Lee, J.C., Gutell, R.R., 2004. Diversity of base-pair conformations and their occurrence in rRNA structure and RNA structural motifs. Journal of Molecular Biology, 344(5), 1225–1249

Peter J.R., 2005. iGenetics: A Molecular Approach. San Francisco:  Pearson Education

Russell, P., 2002. IGenetics. San Francisco: Benjamin Cummings

Sheridan, C., 2011. Gene therapy finds its niche. Nature Publishing Group, 29(2), 121–128

Watson, J.D., 2007. Recombinant DNA: genes and genomes: a short course. San Francisco: W.H. Freeman