The Significance of Major Discoveries in Modern Biology

Biology has transformed and changed over the years. It has flourished and matured into sophistication. Modern biology has birth numerous scientific discoveries. This growth has led to new discoveries in DNA, how evolution occurred, cellular biology and biotechnology. These discoveries have determined scientific progress and a better quality of life. Knowing what those discoveries are and who constructed the course these discoveries are worthy to be examined. This breakthrough is appreciable and refined our agricultural production, health, medicine and environmental control. Modern biology social impact has caused significant changes in human life. This essay will provide an overview of the 3 most important discoveries that have occurred and what their significance is to society.

Genetic Fingerprinting/DNA Profiling

DNA profiling is the process of determining an individual’s DNA characteristics, which are as unique as fingerprints (Moreno). DNA profiling statistically analysis of the output of DNA. It is used to determine the probability that another nonrelated individual might share the same DNA fingerprint as the one being sampled when evidence is collected (Moreno). This process is commonly used as a forensic technique in criminal investigations. It is also used in paternity testing, and in genealogical and medical research. DNA profiling was developed by Sir Alec Jeffreys (Moreno). To analyze DNA Jeffreys used an electropherogram (Moreno). It produces a graph that contains peaks. The peaks representing the different alleles characteristics that particular sample contains (Moreno). A forensic scientist will evaluate the data and calculate the occurrence of that profile combination to the population (Moreno). This evidence is presented and accepted in a court of law. DNA profiling needs to be measured against the population to make the evidence legitimate in criminal investigations.

The human genome is 99 percent identical among all individuals (Moreno). There is enough DNA in all of us to distinguish one individual from another except for identical twins(monozygotic) (Moreno). Analysts use different DNA markers to indicate the differences among us (Godde). Crime laboratories use (STR) markers provided by the national DNA database to compare DNA samples. STR stands for a short tandem repeat, this analysis determines the number of repetitive DNA sequences (Godde). STR looks for two to seven base pairs in length along the DNA structure (Godde). The particular locations of the chromosomes and the exact number of which these characteristics varies among individuals in a population (Godde). A common method used for collecting a sample is a buccal swab. Sometimes samples are obtained from blood relatives to provide an indication of an individual’s DNA profile (Godde). DNA profiling technology is a powerful tool that has brought a tremendous change to the criminal justice and their ability to use it in crime detection. Without it, career criminals can continue to commit crimes and wreak havoc on society. Without DNA profiling the courts don’t have solid proof of committing a crime. It gives the court due process for the victim and the suspect.

Restriction Enzyme

Restriction enzymes is an enzyme (catalyst to bring a specific biochemical reaction) that cleaves DNA into fragments near a specific site within the molecule (Harris). While another enzyme called DNA ligase attached itself and rejoined the DNA fragments with complementary ends. Restriction enzymes have the ability to cut and paste DNA. Bacteria can be found in restriction enzymes. The bacteria use the enzymes to kill viruses. The enzymes attack the virus’s DNA and break it down into inoperable fragments. Restriction enzymes operate by using shape-to-shape detection. When it finds a particular DNA sequence with a shape that matches a fragment of the enzyme it is referred to as the recognition site. The restriction enzymes will wrap around the DNA and cause a break in both strands of the DNA molecule. The discovery of these enzymes was an essential key to the development of genetic engineering technology. Restriction enzymes are classified into four different types (Harris). Each restriction enzyme type recognizes a different and precise recognition site in a DNA sequence. Recognition sites are usually only short – 4-8 nucleotides. Each class of enzymes recognize certain short DNA sequences and carry out the cleavage of DNA to give precise fragments to Ribose 5-phosphate (Harris).

Restriction enzymes make two incisions one time, through each sugar-phosphate backbone of the DNA double helix (Harris). Enzymes are found in bacteria and archaea, they provide a defense mechanism against viruses (Harris). Type I enzymes cleave at sites that are remote from the recognition site. It requires ATP and S-adenosyl-L-methionine adenosine (when methionine reacts to adenosine triphosphate or ATP) to function (Harris). Type I enzymes are multifunctional. It is can capable of restriction and modifies activity, depending on the methylation status of the target DNA (Harris). Type II enzymes cleave at a short distance from the recognition site. It requires magnesium (Harris). They only have one function and are commonly used. Type III enzymes cleave at short distances from the recognition site. It does require ATP. S-adenosyl-L-methionine causes a reaction but is not needed. They make up the prokaryotic DNA restriction-mechanisms that protect the organism against foreign DNA (Harris). Type IV enzymes solely function is to target methylated DNA.

The genetic engineering field is nothing without this discovery. Restriction enzymes allow scientists to create recombinant DNA molecules (Harris). These molecules contain DNA from different sources. With the source, DNA molecules can be cut with restriction enzymes allowing scientist to cut DNA into fragments and customize them into new combinations with DNA fragments from other molecules (Harris). This technology has birthed many advances in the medical field. One example is human insulin made with bacterial cells. Restriction enzymes are a tool used for DNA cloning and DNA fingerprinting for biotechnology research. Most large organisms have very complex DNA it becomes difficult to manipulate and study. DNA restriction enzymes make it more convenient. The large DNA molecules are cut into smaller fragments. This makes it easier for genetics procedures (Harris). When a DNA segment is digested through a restriction enzyme, the fragments left behind can be observed using a method called gel electrophoresis (Scitable). Gel electrophoresis is used to disperse pieces of DNA according to their size (Scitable). Digestion of DNA segments can occur in 3 different ways.

One way is when two portions of a DNA segment are digested individually with a different restriction enzyme (Scitable). Another way is for the third portion of the DNA is double-digested with 2 restriction enzymes at the same time (Scitable). Once the segment is separated using gel electrophoresis the DNA fragments are recorded (Scitable). The total length of each fragment indigestion will be equal (Scitable). The final portrayal of the DNA segment that shows the locations of the restriction sites is called a restriction map. Restriction maps were also created from restriction enzymes. A restriction map is a diagram of a DNA showing where restriction enzymes have cut the molecule (Harris) and the size of the fragments that are produced. The restriction sites are used as markers to study of the DNA molecule and to help geneticists locate important genetic areas (Harris). A restriction map of a DNA molecule is constructed through a computer program that will find all the recognition sites that are present for every restriction enzyme known (Scitable). The most common application of restriction mapping in modern biology is determining the orientation of a cloned insert (Scitable). It requires restriction maps of the cloning vector and the insert.

Restriction fragment length polymorphisms (RFLP) are markers used in the human genome. RFLP is caused by mutations that occur at the recognition site for a particular restriction enzyme (Harris). The recognition site is altered so that the restriction enzyme can no longer cut there. This causes one long fragment. Because of the mutations in the DNA sequence, they will be inherited from one generation to the next (Harris). These mutations are a valuable tool for biologists to map human DNA and help scientists who are conducting DNA fingerprinting.

RNA Interference

RNA interference or (RNAi) is the process of the cellular mechanism that use the gene’s own DNA sequence to turn it off (UMass). Scientist call this process in research silencing. A variety of organism’s RNAi is triggered by double-stranded RNA (dsRNA). RNA molecules hinder translation by neutralizing targeted mRNA molecules (UMass). Historically, RNA interference was known by other names, including co-suppression, post-transcriptional gene silencing (PTGS), and quelling (UMass). The study and the discovery of RNAi have become a phenomenon in the suppression of desired genes. RNAi is as precise, and efficient way for gene suppression. Two small ribonucleic acids (RNA) molecules, microRNA (miRNA) and small interfering RNA (siRNA) are the central components to RNA interference (UMass). The direct products of genes are RNA’s. The small RNAs direct enzymes to destroy the messenger RNA (mRNA) molecules (UMass). This will decrease the mRNA and their activity by preventing translation. transcription can be repressed by the pre-transcriptional silencing of RNA interference (UMass). RNA interference plays an important role in defending cells against viruses and influences development (UMass).

During RNAi long dsRNA is cut by restriction enzymes into small fragments. These small interfering RNAs (siRNA) fragments bind to proteins called the Argonaute proteins (UMass). When siRNA bind to an Argonaute protein one strand of the dsRNA is removed. This leaves the remaining strand available to bind to messenger RNA target sequences. RNAi is used by researchers to learn about genes and their function (UMass). siRNAs are designed and manufactured to match genes. It’s cheap to make and can be administered to cells. RNAi has a more therapeutic approach to treat diseases and genetic disorders. Some diseases are a result of the unwanted activity of a gene such as cancers (UMass). There are several clinical trials testing siRNA drugs. RNAi reflects the earliest form of cellular mechanisms that regulate biological functions. Argonaute proteins help RNAs maintain chromosome structure and give it stability.

Humans can make more than 500 microRNAs (a cellular RNA fragment that prevents the production of protein binding and destroying the messenger RNA that would have produced the protein) (UMass). The unsuitable production of microRNAs has been linked to several diseases. microRNAs have been recognized for their expressions being altered in different diseases. cancer, hepatitis C infection and metabolic disease. microRNAs signature patterns are overexpressed underexpressed in particular diseases. One example is tumors, the microRNAs are involved in tumor development by hindering the tumor suppressor gene. Drugs used to treat disease-causing microRNAs are now being tested as therapies for debilitating diseases. microRNA therapy uses antisense prevention or replacement. Antisense therapy is a form of treatment for genetic disorders or infections. The function of antisense is to regulate gene expression, it is produced synthetically for the use of gene knockdown. Technological advancement makes it easier for the administration of miRNA through injections. These advantages make microRNA therapy an attractive target because it can manipulate the body functions effectively.

Modern biology and its development have contributed most extensively to the world. Scholars develop improvements to push our future into the future with hope and further thinking. Thanks to the works of our great minds most people have a better chance at life. Biology helps us understand the complex forms of life. It is essential to understand the intricate details of life. We began to solve problems such as disease, famine, preservation of the ecosystem, animals, plants, and most important humans. Biology gives humanity a new perspective of the world. It develops an interest in preserving living organisms to its highest function. Biology is creating solutions to the challenges living organisms face. Without these advancements in biology, we probably would have never realized how important it is to maintain a healthy life for all on earth.