Life Sciences Term 2

Mutations, genetic engineering and the applications of this

MUTATIONS
This is a sudden change in the genetic composition of an organism. it contributes to genetic  variation.

Gene mutation
A gene mutation is a change in the genetic material/DNA sequencing in the cell affecting only a few base pairs in just a single gene.   

Chromosomal mutation
Refer to changes in the normal structure or number of chromosomes. 

CAUSES OF MUTATIONS

• Nuclear radiation, exposure to ultra violet light and x-rays
• Viruses; unhealthy diet and alcohol 

EFFECTS OF MUTATIONS
Mutations assist the organism to adapt to its environment:

• HARMFUL MUTATIONS : causes changes in DNA that can cause errors in protein sequencing, that can result in partially or completely non- functional protein  HARMLESS MUTATIONS : Have no effect on the structure or functioning of the organism
  
• USEFUL MUTATIONS: Can be advantageous to the organism and they are passed on from parent to offspring.

Examples of mutations to be studied:

• Haemophilia, Colour-blindness and Down syndrome

Genetic Engineering: 
This is the process where scientists alter, swap or manipulate the genes on the DNA, to produce an organism with desirable characteristics. Genetic engineering uses biotechnology to satisfy human needs.

The following table shows the advantages and disadvantages of genetic engineering which is no longer in the exam guidelines but still useful to show learners:

Advantages of Genetic engineering	Disadvantages of Genetic engineering
Production of medication/ resources cheaply Control pests with specific genes inserted into a crop Uses specific genes to increase crop yields/ food security Selecting genes to increase shelf- life of plant products	Expensive/ research money could be used for other needs Interfering with nature or immoral Potential health impacts Unsure of long term effects

The examples of genetic engineering to be studied: Cloning, stem cell research and genetically modified organisms.

Cloning
This is the process by which genetically identical organisms are produced using biotechnology.

Process:

• With cloning, the nucleus of a somatic cell (2n) of one organism is removed
• An ovum (n) is taken from an ovary of another organism
• The nucleus of the ovum is destroyed
•  The somatic cell’s nucleus (2n) is then placed inside the ovum
• The ovum is put back into a uterus where it is allowed to grow and differentiate into an embryo
• When the new offspring is produced, it is identical to the original organism.

A sheep called Dolly was cloned successfully in 1997.

Reference: https://www.slideshare.net/AhmedAyan/cloning-animal-cloning-clone

Stem Cell research:
A stem cell is any cell in the body that can differentiate into any specialised type of tissue in the body. 

SOURCES OF STEM CELLS
Stem cells can be harvested from:

• Umbilical cord blood (once a baby has been born)
• A foetal blastocyst
• Bone marrow.

USES OF STEM CELL THERAPY
To treat:

• Cancers like Leukemia
• Degenerative diseases like Multiple Sclerosis
  
• Diabetes mellitus where the pancreas no longer produces insulin
• Muscle damage
  
• Organ damage 
• Certain genetic diseases in conjunction with gene therapy. 

Genetically modified organisms : THE PROCESS:

Benefits of genetic modification: e.g. The Advantages of Genetically Modified Crops

• Better for the environment
• Since GMOs require much less chemicals to thrive, the impact on the environment is lessened. The pesticides and other chemicals commonly used on non GMO crops emit greenhouse gases and pollute the ground soil
• Resistance to disease
• One of the modifications made to the crops is an added resistance to disease that would normally kill off the crops. This keeps the yields high and the prices for the consumers low
• Sustainability
• GMOs provide a stable and efficient way to sustain enough crops to feed the ever growing population of people in the world. This was the main goal of GMO crops in the first place
• Increased flavour and nutrition
• Along with resistances to insects and disease, the genes of the crops can also be altered to have a better flavor and increased nutritional value. This is good all around
• Longer shelf life
• Genetically modified foods have a longer shelf life. This improves how long they last and stay fresh during transportation and storage
• Keeps it affordable
• One of the biggest effects that the use of GMOs has had on our everyday life is the prices of produce and other foods. Since more crops can be yielded, the prices can be much lower.

PATERNITY TESTING
An analysis, usually of the DNA or blood type of a mother, child, and possible father, to estimate the probability that the man is the biological father of the child.

Blood grouping

• Genotypes of the mother and the suspected man's blood groups are compared with those of the child
• If the genotypes for the blood groups of the man and the mother could not lead to the blood group of the child the man is not the father of the child
• If the genotypes for the blood groups of the man and the mother could lead to the blood group of the child it cannot be said with certainty that the man is the father of the child because other males have the same blood group.

DNA profiles

• Every person except identical twins has her/his own unique DNA profile
• It can be described as an arrangement of black bars representing DNA fragments of the person
• It is used to:
• Identify paternity