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DNA TECHNOLOGY

INTRODUCTION

DNA carries all of the genetic information for life. One enormously long DNA molecule forms each of the chromosomes of an organism, 23 of them in a human. The fundamental living unit is the single cell.

DNA technology has helped humankind in many ways: in the verification of one’s identity i9n the treatment pf genetic disorders, and the improvement of crop varieties and animal breeds.

OBJECTIVES

1. Discuss the important techniques employed in DNA technology.

2. Cite some of the uses and potential applications of DNA technology

3. Explain the positive and negative consequences of the use of DNA technology

ACTIVITY I

Discussion on techniques applied in DNA technology

DNA technology refers to a wide range of techniques used to study, improve, create or manipulate the genetic material. Through DNA technology genes are identified that control a desired trait extract them, copy them and insert them into another organism.

TECHNIQUES IN DNA TECHNOLOGY

1. Sequencing, - technique used to determine the nucleotide sequence of DNA (deoxyribonucleic acid). The nucleotide sequence is the most fundamental level of knowledge of a gene or genome. It is the blueprint that contains the instructions for building an organism, and no understanding of genetic function or evolution could be complete without obtaining this information.

· Different methods of DNA sequencing:

A. Maxam and Gilbert method.

- is a method of DNA sequencing developed by Allan Maxam and Walter Gilbert in 1976–1977. This method is based on nucleobase-specific partial chemical modification of DNA and subsequent cleavage of the DNA backbone at sites adjacent to the modified nucleotides.

B. Chain termination method.

- is any chemical reaction that ceases the formation of reactive intermediates in a chain propagation step in the course of a polymerization, effectively bringing it to a halt.

C. Semi-automated method.

- A semi-automated system, whereby PCR-amplified biotinylated genomic or plasmid DNA is immobilized on streptavidin-coated magnetic beads, has been developed.

D. automated method.

Automated DNA sequencing utilizes a fluorescent dye to label the nucleotides instead of a radioactive isotope. ... The system automatically identifies the nucleotide sequence and saves the information on the computer. Thus, only a review of the data is necessary to ensure no anomalies were misidentified by the computer.

E. Pyrosequencing.

- is a method of DNA sequencing based on the "sequencing by synthesis" principle, in which the sequencing is performed by detecting the nucleotide incorporated by a DNA polymerase. Pyrosequencing relies on light detection based on a chain reaction when pyrophosphate is released.

F. The whole-genome shotgun sequencing method.

- method entails sequencing many overlapping DNA fragments in parallel and then using a computer to assemble the small fragments into larger contigs and, eventually, chromosomes. The result is a large-scale map that tells the exact order for each piece of sequenced DNA.

G. Clone by the clone sequencing method.

-This method requires the genome to have smaller sections copied and inserted into bacteria. The bacteria then can be grown to produce identical copies, or “clones,” containing approximately 150,000 base pairs of the genome that is desired to be sequenced.

E. Next-generation sequencing method.

- Next-generation sequencing (NGS) is a massively parallel sequencing technology that offers ultra-high throughput, scalability, and speed. The technology is used to determine the order of nucleotides in entire genomes or targeted regions of DNA or RNA.

2. Analysis- has been considered to identify fibre type. ISO 18074:2015e specifies a testing method for DNA analysis to identify animal fibres such as wool, cashmere and yak.

*DNA analysis methods

A. Polymerase chain reaction (PCR)-

B. Gel electrophoresis.

C. DNA sequencing.

3. cutting-and-pasting of DNA-

The discovery of enzymes that could cut and paste DNA made genetic engineering possible. Restriction enzymes, found naturally in bacteria, can be used to cut DNA fragments at specific sequences, while another enzyme, DNA ligase, can attach or rejoin DNA fragments with complementary ends.

Common forms of DNA technology

1. polymerase chain reaction-

- is a method widely used to rapidly make millions to billions of copies of a specific DNA sample, allowing scientists to take a very small sample of DNA and amplify it to a large enough amount to study in detail.

2. DNA cloning-

DNA cloning is the starting point for many genetic engineering approaches to biotechnology research.

Large amounts of DNA are needed for genetic engineering. Multiple copies of a piece of DNA can be made either by using polymerase chain reaction (PCR) or by cloning DNA in cells.

3. gel electrophoresis.

Gel electrophoresis is a laboratory method used to separate mixtures of DNA, RNA, or proteins according to molecular size. In gel electrophoresis, the molecules to be separated are pushed by an electrical field through a gel that contains small pores.

ACTIVITY II

USES AND POTENTIAL APPLICATIONS OF DNA TECHNOLOGY

1.DNA testing can also be used to identify pathogens, (referred to as an infectious agent, or simply a germ).

2. identify biological remains in archaeological digs,

3. trace disease outbreaks,

4. and study human migration patterns.

5. In the medical field,

a. DNA is used in diagnostics,

b. new vaccine development,

c. and cancer therapy

6. It has found use in pharmacology,

7. genetic engineering in disease prevention,

8. in increasing agricultural growth,

9. in detection of disease and crime (forensics)

10. forensics. bioinformatics.

11. DNA technology has also had a major impact on the pharmaceutical industry, agriculture,

12. DNA technology and gene cloning are essential to the pharmaceutical industry and medicine.

13. DNA technology is being used to help diagnose genetic diseases, such as sickle-cell disease and Huntington's disease.

14. DNA technology is also critical to developing vaccines. Vaccines are harmless versions of a pathogen, such as a bacterium or virus. .

15. Therapeutic hormones, such as insulin and human growth hormone, are also the result of DNA technology in medicine.

Agriculture

You have likely heard of genetically modified organisms, or GMOs. These are organisms that have genes from artificial means. GMOs are used for a variety of agricultural purposes, such as growing larger plants with higher yields, creating pest-resistant crops and improving the nutritional value of crops.

For example, in India, a salt-resistant gene has been inserted into rice so that it can grow in water that is three times as salty as seawater! Another new variety of rice now exists that has very high beta-carotene levels to help reduce vitamin A deficiencies in certain parts of the world.

DNA technology doesn't just make bigger, better food, though. It's also being used to create food products that have medicinal benefits. For example, a new rice strain has been engineered that has milk proteins that can be used to treat infant diarrhea. There are other medicinal food products being designed, like corn that can treat cystic fibrosis and duckweed to treat hepatitis.

ACTIVITY III

Explain negative consequences of the use of DNA technology

Some critics argue that people using ancestry sites should have the ability to decide whether police can use their DNA data in crime searches.

Some critics also say that police forces, uploading DNA to such websites in search of matches, should only be able to do so in cases of extremely serious crimes, like murder and rape.

The disadvantage of using DNA technology is that sometime the gene transfers to the non -target species.