INTRODUCTION TO GENETIC ENGINEERING:

            Genetic engineering refers to the direct manipulation of DNA to alter an organism's characteristics (phenotype) in a particular way.

            Joining together of DNA molecule from two different species that are inserted into a host organism to produce new genetic combination that are of value to science, medicine, agricultural and industry.

WHAT IS GENETIC ENGINEERING?

* Genetic engineering, sometimes called genetic modification, is the process of altering the DNA in an organism's genome.

* This may mean changing one base pair (A-T or C-G), deleting a whole region of DNA, or introducing an additional copy of gene.

* It may also mean extracting DNA from another organism genome and combining it with the DNA of that individual.

* Genetic engineering is used by scientists to enhance or modify the characteristics of an individual organism.

* Genetic engineering can be applied to any organism, from a virus to a sheep.

* For example, genetic engineering can be used to produce plants that have a higher nutritional value or can tolerate exposure to herbicides.

HOW DOES GENETIC ENGINEERING WORK?

To help explain the process of genetic engineering we have taken the example of insulin, a protein that helps regulate the sugar levels in our blood.

* Normally insulin is produced in the pancreas, but in people with type 1 diabetes there is a problem with insulin production.

* People with diabetes therefore have to inject insulin to control their blood sugar levels.

* Genetic engineering has been used to produce a type of insulin, very similar to our own, from yeast and bacteria like E.Coli

* This genetically modified insulin, 'Humulin' was licensed for human used in 1982.

THE GENETIC ENGINEERING PROCESS:

1. A small piece of circular DNA called a plasmid is extracted from the bacteria or yeast cell.

2. A small section is then cut out of the circular plasmid by restriction enzymes, "molecular scissors".

4. The genetically modified plasmid is introduced into a new bacteria or yeast cell.

5. This cell then divides rapidly and starts making insulin.

6. To create large amount of the cells, the genetically modified bacteria or yeast are grown in large fermentation vessels that contain all the nutrients they need. The more the cells divide, the more insulin is produced.

7. When fermentation is complete, the mixture is filtered to release the insulin.

8. The insulin is then purified and packaged into bottles and insulin pens for distribution to patients with diabetes.

An illustration showing how genetic modification is used to produce insulin in bacteria.

WHAT ELSE IS GENETIC ENGINEERING USED FOR?

* The first genetically modified organism to be created was a bacterium, in 1973.

* In 1974, the same techniques were applied to mice.

* In 1994 the first genetically modified foods were made available.

* Genetic engineering has a number of useful applications, including scientific research, agriculture and technology.

* In plants, genetic engineering has been applied to improve the resilience, nutritional value and growth rate of crops such as potatoes, tomatoes and rice.

* In animals it has been used to develop sheep that produce a therapeutic proteins in their milk that can be used to treat cystic fibrosis or worms that glow in the dark to allow scientist to learn more about diseases such as Alzheimer's.

ALZHEIMER'S DISEASE AND THE WORM:

* The nematode worm, C.elegans, only has around 300 cells in its entire nervous system, making it a very simple model for studying Alzheimer's diseases.

* Also, due to the fact the worm is nearly transparent, when the nerve cells are labeled with green fluorescent protein (GFP), if is possible to watch the location and activity of various structures and proteins under the microscopes.

* The genetic material of C.elegans can easily be genetically modified to make the worm produce specific proteins the researchers want to study.

* In human, the APP gene codes for a protein associate with the amyloid plaques that are characteristics of people with Alzheimer's diseases.

* So, to study Alzheimer’s, the researchers genetically engineered the nerve cells of the worm to contain the APP gene, effectively giving it Alzheimer's.

* By tagging the APP protein produced in the worm with green fluorescent protein it was possible to see that all the cells that made contact with APP died as the worm got older.

* The researcher where then able to monitor the progression of the Alzheimer's disease in the worm go on to apply their findings to understanding the role of APP in humans with Alzheimer's disease.

GENETIC TRAITS:

•       A phenotype is an individual’s observable traits, such as height, eye color, and blood type. The genetic contribution to the phenotype is called the genotype. Some traits are largely determined by the genotype, while other traits are largely determined by environmental factors.”

CAN PERSONALITY TRAITS BE GENETIC?

•       Behavioral genetics study of personality has made it clear that genes are important. In fact, a number of personality traits have been identified as having a genetic basis. For example, family studies have led to the discovery that generalized anti-social behavior is passed down through genetic inheritance.”

HOW DO GENES AFFECT OUR BEHAVIOR?

•       “It is difficult to ascertain whether genetics ("nature") or the environment ("nurture") has a stronger influence on behavior. It is generally believed that human behavior is determined by complex interactions of both nature and nurture.

IS BEHAVIOUR INHERITED?

•       Environmental factors also can influence human behavior. Behavioral geneticists work to discover how much of people's behavior is determined by the genetic information they inherited from their parents and how much is caused by their living conditions, learning choices, and other influences from the world around them.

HUMAN BEHAVIOURAL GENETICS:

            Human behaviour genetics is a subfield of the field of behaviour genetics that studies the role of genetic and environmental influences on human behaviour. Classically, human behavioural geneticists have studied the inheritance of behavioural traits. The field was originally focused on testing whether genetic influences were important in human behavior (e.g., do genes influence human behavior). It has evolved to address more complex questions such as: how important are genetic and/or environmental influences on various human behavioral traits; to what extent do the same genetic and/or environmental influences impact the overlap between human behavioral traits; how do genetic and/or environmental influences on behavior change across development; and what environmental factors moderate the importance of genetic effects on human behavior (gene-environment interaction).The field is interdisciplinary, and draws from genetics, psychology, and statistics. Most recently, the field has moved into the area of statistical genetics, with many behavioral geneticists also involved in efforts to identify the specific genes involved in human behavior, and to understand how the effects associated with these genes changes across time, and in conjunction with the environment.

METHODS OF HUMAN BEHAVIOURAL GENETICS:

•       Human behavioural geneticists use several designs to answer questions about the nature and mechanisms of genetic influences on behaviour. All of these designs are unified by being based around human relationships which disentangle genetic and environmental relatedness.

•       So, for instance, some researchers study adopted twins: the adoption study. In this case the adoption disentangles the genetic relatedness of the twins (either 50% or 100%) from their family environments. Likewise the classic twin study contrasts the differences between identical twins and fraternal twins within a family compared to differences observed between families. This core design can be extended: the so-called "extended twin study" which adds additional family members, increasing power and allowing new genetic and environmental relationships to be studied. Excellent examples of this model are the Virginia 20,000 and the QIMR twin studies.

Also possible are the "children of twins" design (holding maternal genetic contributions equal across children with paternal genetics and family environments) and the "virtual twins" design - unrelated children adopted into a family who are very close or identical in age to biological children or other adopted children in the family. While the classical twin study has been criticized they continue to be of high utility. There are several dozen major studies ongoing, in countries as diverse as the USA, UK, Germany, France, the Netherlands, and Australia, and the method is used widely in fields as diverse as dental caries, BMI, ageing, substance abuse, sexuality, cognitive abilities, personality, values, and a wide range of psychiatric disorders. This is broad utility is reflected in several thousands of peer-review papers, and several dedicated societies and journals (See Twin study).

GENETIC INFLUENCE ON PERSONALITY:

•       Behavioral genetics' study of personality has made it clear that genes are important. In fact, a number of personality traits have been identified as having a genetic basis. For example, family studies have led to the discovery that generalized anti-social behavior is passed down through genetic inheritance.

Biological Influences on Human Behavior: Genetics & Environment

Human Behaviors:

Sometimes I wonder if my sister and I are really part of the same family. We have the same parents and we definitely look alike, but our personalities are so different! This is because even though we have a similar genetic makeup, our external environment also plays a substantial role in shaping us as individuals.

Twins are even more interesting than regular siblings because even identical twins, who have the exact same DNA, can look and act differently from one another. Because different aspects of our behaviors are influenced by our genes, the environment, or a combination of the two, it can be difficult to determine which is more influential for specific behaviors.

For example, your natural features, such as your hair and eye color, are determined by genetics. But how you style that hair and what kind of sunglasses you wear over those eyes, well, those may be part of your genetic personality, but they're also likely influenced by the people you hang out with and other social cues in your environment.

Twin Studies

Because identical twins have the same DNA, they are often used to help scientists understand which behaviors may be determined by genetics and which may be influenced by our environment. As exact copies of each other, sets of identical twins can be compared with other sets of identical twins to see how the environment affects their individual behaviors.

For example, scientists may compare identical twins that were separated at birth to identical twins that grew up in the same household. This allows them to examine how different environments influence the same genetic makeup. Other studies may compare identical twins that were raised together to fraternal twins, who, like normal siblings, only share about half of their DNA.

While there are no definitive answers, what these studies do generally show is that neither genetics nor the environment is more important than the other when it comes to some of the more complex behaviors. For example, genetic makeup accounts for about half of the variation we see in human personalities and intelligence. But this means that the other half of the variation we see in people comes from their environmental surroundings. So for some behaviors, both our genes and the environment play an equally important role.

Genetics & Behavior

It may be tempting to think that genetically influenced behaviors come from specific genes. However, just because a behavior has a genetic basis doesn't mean that there is a gene that 'controls' that trait. Genes don't actually control behaviors, they just facilitate certain reactions to our environment.

For example, many animals in nature are monogamous, which is a genetically influenced behavior. But there is no specific gene that causes monogamous behavior in these animals. Instead, certain genes produce proteins with receptors that respond positively to the scent of their mate. And it's this positive response that began with genetics and then is triggered by the environment that keeps the couple close to each other.

Humans have similar responses to other people; we like being around others for a reason! Human brains are genetically programmed to respond to social recognition and bonding with others. We are a very social species and we form complex relationships with friends and family. However, what we don't know much about is how our brains do this. Hormones and hormone receptors are major players, but the jury is still out on just how those mechanisms are involved in forming relationships and bonding with others.

GENETICS AND HERIDITY:

            Heredity is the passing on of traits from parents to their offspring, either through asexual reproduction or sexual reproduction; the offspring cells or organisms acquire the genetic information of their parents. ... The study of heredity in biology is called genetics, which includes the field of epigenetics.

GENETIC DISORDER:

•                   Genes are the building blocks of heredity. They are passed from parent to child. They hold DNA, the instructions for making proteins. Proteins do most of the work in cells. They move molecules from one place to another, build structures, break down toxins, and do many other maintenance jobs.

Sometimes there is a mutation, a change in a gene or genes. The mutation changes the gene's instructions for making a protein, so the protein does not work properly or is missing entirely. This can cause a medical condition called a genetic disorder.

You can inherit a gene mutation from one or both parents. A mutation can also happen during your lifetime.

There are three types of genetic disorders:

•       Single-gene disorders, where a mutation affects one gene. Sickle cell anemia is an example.

•       Chromosomal disorders, where chromosomes (or parts of chromosomes) are missing or changed. Chromosomes are the structures that hold our genes. Down syndrome is a chromosomal disorder.

•       Complex disorders, where there are mutations in two or more genes. Often your lifestyle and environment also play a role. Colon cancer is an example.

Genetic tests on blood and other tissue can identify genetic disorders.

CONCLUSION:

            In my opinion genetic engineering and the experimentation with human and nature genes has to continue, but it should be limited which is the human essence. I mean all experiments that could helps people, plants or foods to find the cure and treatments for diseases are necessaries because four our fault, the globalization and the behaviors have affected our environment and have made the world worst. So in that case and without involve basics aspects for futures generations and considering rules to put limits to the science, I think that GMO as a good way to save us. Finally, I would like to emphasize in the following sentence: God or whatever be your supreme believing is the unique that can determine how we will be physically in our life, we can´t claim being God and trying to manipulate things that just he could be do.