DNA - The Code of Life; and RNA - PDF Notes

DNA - The Code of Life; and RNA Key Concepts: DNA Structure and Coding, Protein Synthesis, Mutations, Application of DNA Technology The Answer Series Part 1...

DNA - The Code of Life; and RNA Key Concepts: DNA Structure and Coding, Protein Synthesis, Mutations, Application of DNA Technology The Answer Series Part 1 Page 1.2 - 1.14 Created by Ms. C.R. Els  DNA Structure and Coding Key Concepts: Structure and Function of the Nucleus, Nucleic Acids, Location of DNA, Chromosomes and Genes, Who Discovered the Structure of DNA, Structure of DNA, Role of DNA, DNA Replication, Mitochondrial DNA, Location of RNA, Structure of RNA, Types of RNA, Function of RNA, Similarities Between DNA and RNA Page 1.2 - 1.8 Structure and Function of the Nucleus The nucleus is surrounded by a double nuclear membrane with pores. The pores form a passage between the nucleus and cytoplasm of the cell. The nuclear membrane encloses the nucleoplasm (a jelly-like liquid). A small round body known as the nucleolus is suspended in the nucleoplasm. A mass of thread-like structures known as the chromatin network also occurs in the nucleus. Chromatin is chromosomal material made up of DNA, RNA and histone proteins as found in a non-dividing cell. When a cell divides, the chromatin network coils and thickens into separate, shorter thread-like structures known as chromosomes. The chromosomes are the carriers of genetic material Nucleic Acids in the cell. Nucleic acids are organic molecules that control the synthesis of proteins in all living cells by storing and transferring genetic information. Proteins make up much of the structure of the body. Enzymes are proteins and control chemical processes inside cells. In this way, they ultimately control the structure and functioning of all living organisms. They are therefore referred to as the 'molecules of life'. There are 2 types of nucleic acids found in cells. Deoxyribonucleic acid - DNA Ribonucleic acid - RNA Location of DNA DNA occurs mainly in the nucleus where it forms part of the chromatin network/chromosomes. It is therefore known as chromosomal DNA. A small amount of DNA occurs outside the nucleus in mitochondria of plant and animal cells and chloroplasts of plant cells. It is therefore known as extranuclear DNA. DNA found in the mitochondria is known as mitochondrial DNA (mtDNA). It is passed from mother to child and is thus used to trace maternal lines through generations. Since it rarely undergoes changes due to mutations and remains largely unaltered, it is very useful in determining relatedness between individuals. Created by Ms. C.R. Els Page 1 Chromosomes and Genes Chromosomes are long thread-like structures composed of DNA that is wrapped around proteins called histones. A short segment of a DNA molecule that codes for a particular protein is known as a gene. Each gene carries the code for the synthesis of a particular protein. Proteins determine the characteristics (structure and functioning) of an organism. Chromosomes are only visible in dividing cells. In non-dividing cells the DNA appears as a chromatin network. Who Discovered the Structure of DNA? Scientists James Watson and Francis Crick formulated the double helix structure of DNA in 1953. Several scientists paved the way for this discovery. Initially research showed that genetic material was DNA, but the structure of the molecule was still unknown. It then became known that there was an equal number of adenine and thymine bases, as well as equal numbers of guanine and cytosine bases in a DNA molecule. Another team of scientists, Maurice Wilkins and Rosalind Franklin, were trying to work out the structure of DNA in the early 1950's. They took X-ray photographs of the DNA molecule. Through her continued research, Rosalind Franklin summised that DNA was helix-shaped. Wilkins showed Franklin’s X-ray photograph to Francis Crick without her permission. Watson and Crick used information from the X-ray photograph to build a 3D model of the structure of DNA. Francis Crick, James Watson and Maurice Wilkins won the Nobel prize for the discovery of the structure of DNA. Rosalind Franklin died of cancer in 1958 and her valuable contributions were never honoured and she did not receive credit. The structure of DNA is known as the Watson and Crick model. 1865 By means of pea plant experiments, Gregor Mendel finds that each characteristic is controlled by a specific gene. Determined that there are equal numbers of adenine and 1949 thymine bases and equal numbers of guanine and cytosine bases in a DNA molecule. 1952 Rosalind Franklin takes X-ray photos of DNA. Maurice Wilkins shows the X-ray photo to Watson and Crick. 1953 James Watson and Francis Crick formulate the double helix structure of DNA using a 3D model. 1962 James Watson, Francis Crick and Maurice Wilkins win Nobel Prize for the discovery of the structure of DNA. Created by Ms. C.R. Els Page 2 Structure of DNA DNA is a giant molecule consisting of two strands that are twisted to form a double helix. When unwound, it looks like a ladder. DNA is a polymer made up of a large number monomers. These monomers are nucleotides Nucleotides: Each nucleotide is made up of the following: A sugar molecule - deoxyribose A phosphate molecule Nitrogenous bases Nitrogenous bases: There are four different nitrogenous bases in DNA: Adenine (A), Cytosine (C), Thymine (T) and Guanine (G). There are therefore four different nucleotides. These four bases are the foundation of the genetic code, instructing cells on how to create enzymes and other proteins. These four nucleotides contain the same phosphate and deoxyribose sugar, but differ from each other in the base attached. Formation of DNA: In the formation of DNA, the deoxyribose sugar of one nucleotide forms a bond with the phosphate group of another nucleotide. Two long strands resembling the sides of a ladder are formed. The sides of the DNA ladder therefore consist a sugar phosphate backbone with alternating deoxyribose sugar and phosphate molecules. The rungs/steps of the ladder are formed when bases on each strand pair up with each other. This forms base pairs that link by weak hydrogen bonds. This holds the two strands of DNA in the double helix together. Weak hydrogen bonds means that the bonds can be easily broken during DNA replication and protein synthesis. The bases always pair up in the same way - this is known as ‘complementary base pairing’ Adenine always pairs with Thymine (A-T) Cytosine always pairs with Guanine (C-G) Each nucleotide may be repeated in the DNA strand and base pairs can occur in any sequence. The sequence of bases is extremely important as it provides the code that gives instructions for the synthesis of proteins. The sequence of bases in one DNA strand (template) always determines the sequence in the other strand. One DNA strand is therefore the complement of the other strand. Cell division and protein synthesis both rely on base-pairing rules because each half of the DNA double helix acts as a template to be copied in order to create a complete new double helix. Created by Ms. C.R. Els Page 3 Role of DNA Genes: DNA carries the genetic code in the form of genes for the synthesis of proteins. The sequence of nitrogenous bases making up a gene determine the sequence and type of amino acids that will combine to form a particular protein. It can replicate and make an identical copy of itself to ensure that the genetic code is accurately passed from one generation to the next. Non-coding: Approximately 2% of DNA in living cells codes for proteins. This is known as coding DNA. The remaining approximately 98% does not carry information to produce proteins. This is known as non-coding DNA. Initially scientists incorrectly thought that non-coding DNA had no function and they referred to it as “junk DNA". Non-coding DNA varies considerably between individuals and is used in DNA fingerprinting/profiling. Although scientists are still researching the importance of non-coding DNA, certain functions have already been confirmed: It plays an important role in the regulation and control of the expression of genes in the coding DNA. It therefore determines when and where genes are switched ‘on’ and ‘off’. It also protects genes from mutations and controls the process of copying genes during transcription in protein synthesis. DNA Replication DNA replication is the process of making a new DNA molecule from an existing DNA molecule that is identical to the original molecule. This takes place in the nucleus during interphase in the cycle of a cell. Interphase is the period between consecutive cell divisions when the cell performs its normal metabolic activities. The histone proteins together with the DNA form part of a chromosome and they also duplicate during replication. Two identical units known as chromatids are formed. The two chromatids are held together by a centromere. Created by Ms. C.R. Els Page 4  chromatid One chromosome One chromosome BEFORE replication AFTER replication centromere Chromosomes: 1 Chromosomes: 1 DNA molecules: 1 DNA molecules: 2 DNA DNA replication occurs in the following steps: The enzyme helicase first unwinds the DNA, by flattening out its helical structure. Analogy – think about untwisting a rope ladder. Helicase then causes the weak hydrogen bonds between base pairs to break, exposing bases on either strand. Analogy – unzipping a zipper. The DNA strands separate and each of these single DNA strands acts as a template for the formation of a new strand. DNA polymerase links free floating nucleotides in the nucleoplasm to matching base pairs on the exposed template strands by complimentary base pairing. Adenine will bond thymine Guanine will bond to cytosine The two new completed strands are known as daughter DNA molecules. They will rewind to form a double helix which will wind around histone proteins. Their role is to organise and condense the DNA tightly so that it fits into the nucleus. Importance of DNA replication: During mitotic cell division, one mother cell divides into two identical daughter cells. It is essential that DNA makes identical copies of itself before cell division to ensure that each daughter cell contains the same genetic information as the mother cell. Each daughter cell has identical DNA composition to the mother cell. Created by Ms. C.R. Els Page 5  Mitochondrial DNA - mtDNA mtDNA occurs in the mitochondria and is not related to chromosomal DNA that occurs in the nucleus. It is shorter and circular in shape compared to chromosomal DNA. mtDNA and relatedness: It is present in the ovum of the mother and sperm of the father. During fertilisation, only the chromosomes from nucleus of the sperm cell enters the ovum, the body of the sperm containing the mitochondria are discarded. Only the mitochondria containing genetic material that is present in the ovum will be present in the zygote. As a result, mtDNA is passed on to offspring and remains unaltered from mother to child. This is used to determine relatedness in terms of a maternal link between mother and child. A child will have an identical mtDNA sequence to the mother. Scientists can compare the mtDNA sequences of different individuals to determine how closely related they are. The more the mtDNA corresponds, the more closely related the organisms are. If there are many differences in mtDNA, the organisms are not closely related. Location of RNA RNA occurs in the nucleus and the cytoplasm. It also forms part of ribosomes. Structure of RNA RNA is a single strand which is shorter than DNA. Like DNA, RNA is also a polymer made up of nucleotides. Nucleotides: Each RNA nucleotide is made up of the following: A sugar molecule - ribose A phosphate molecule Nitrogenous bases Nitrogenous bases: RNA also has four different nitrogenous bases. It has three nitrogenous bases in common with DNA and one nitrogenous base that is unique: Like DNA it has Adenine (A), Cytosine (C) and Guanine (G). BUT Thymine (T) is replaced by Uracil (U). These four nucleotides contain the same phosphate and ribose sugar, but differ from each other in the base attached. Formation of RNA: In the formation of RNA, the ribose sugar of one nucleotide forms a bond with the phosphate group of another nucleotide. One single long strand forms. The RNA strand therefore consists of a sugar phosphate backbone with alternating ribose sugar and phosphate molecules. The bases always pair up in the same way - this is known as ‘complementary base pairing’ Adenine always pairs with Uracil (A-U) Cytosine always pairs with Guanine (C-G) The four nitrogenous bases of RNA (A, U, C and G) occur in any number and ratio in an RNA strand. Created by Ms. C.R. Els Page 6 Types of RNA There are different types of RNA made in the nucleus which plays a specific role in protein synthesis: messenger RNA - mRNA transfer RNA - tRNA ribosomal RNA - rRNA Messenger RNA (mRNA): It consists of a single strand with an unlimited number of nucleotides. It is formed in the nucleoplasm using DNA as a template. mRNA carries the genetic code from DNA in the nucleus to the ribosomes in the cytoplasm. It therefore acts a messenger. Transfer RNA (tRNA): It consists of a single strand that folds back on itself like a hairpin. tRNA occurs in the cytoplasm. It has three exposed nitrogenous bases on one of the loops. This is known as the anticodon which plays an important role in protein synthesis. tRNA picks up amino acids in the cytoplasm and takes them to the ribosomes where protein synthesis occurs. It therefore acts as a transfer molecule. Ribosomal RNA (rRNA): It consists of a single strand. It forms part of the structure of the ribosome in the cytoplasm. Function of RNA Complete the Venn RNA carries instructions from DNA in the nucleus to the ribosomes in the cytoplasm of Diagram on a cell where it controls the synthesis of proteins to form amino acids. Structure of DNA and RNA Similarities Between DNA and RNA DNA and RNA are both made up of: Polymers Nucleotides that are made up of a sugar, phosphate and nitrogenous base Four nitrogenous bases Practice Exercise Unit 1 They are both responsible for the synthesis of proteins Question 1 - 10 Page 1.47 - 1.48 Created by Ms. C.R. Els Page 7  Protein Synthesis Key Concepts: Protein Synthesis, Transcription of DNA, Translation of RNA to Proteins, Using mRNA Codons to Determine the Sequence of Amino Acids, How Antibiotics Interfere with Protein Synthesis, Genetic Code Summary Page 1.9 - 1.11 Protein Synthesis Protein synthesis is the process whereby proteins are manufactured in living cells. Nucleic acids DNA and RNA control the synthesis of proteins. To synthesise a specific protein, specific types of amino acids have to be joined in a specific sequence. DNA in the nucleus provides the genetic code that determines the type and sequence of the amino acids. Each DNA strand carries the information for the synthesis of several proteins. Each segment of the DNA strand that carries the information to synthesise a particular protein is known as a gene. Only a small section of the DNA strand (the gene) is involved in the synthesis of one protein. Three consecutive nitrogenous bases on the DNA strand are known as a base triplet. This provides the code for a particular amino acid. The sequence of base triplets will therefore determine the sequence of amino acids and thus the type of protein being created. The process of protein synthesis occurs in 2 main steps: Transcription of DNA Translation of RNA to proteins Transcription of DNA DNA occurs in the nucleoplasm and never leaves the nucleus. Protein synthesis occurs outside the nucleus, at the ribosomes in the cytoplasm. The code for synthesis of a specific protein must be transferred from DNA to mRNA which is able to leave the nucleus. This process whereby mRNA obtains the code for protein synthesis from DNA is known as transcription. A complimentary copy of the code from the gene is made by building a single-stranded nucleic acid molecule known as mRNA (messenger RNA) Transcription of DNA occurs in the following steps: Part of a DNA molecule where the desired gene coding for a specific protein is located unwinds by helicase. The weak hydrogen bonds between the complementary base pairs break. This exposes the gene to be transcribed. f RNA polymerase collects free floating RNA nucleotides in the nucleoplasm and pair them to their complimentary base pairs on the exposed DNA template via hydrogen bonds. Thymine is replaced by uracil. The sugar-phosphate groups of these RNA nucleotides are then bonded together by the enzyme RNA polymerase to form the sugar-phosphate backbone of the mRNA molecule. When the gene has been transcribed (when the mRNA molecule is complete), the hydrogen bonds between the mRNA and DNA strands break and the double-stranded DNA molecule re-forms. The mRNA molecule then leaves the nucleus via a pore in the nuclear envelope to travel to the ribosomes in the cytoplasm. Created by Ms. C.R. Els Page 8 What determines which protein is made? A protein is a long chain (polymer) made up of small units (monomers) known as amino acids. There are 20 different amino acids that are involved in proteins synthesis. They combine in various numbers and in various sequences to form thousands of different proteins. It is the order in which the amino acids are linked as well as the number of amino acids that are linked which determines the type of protein being made. What is the role of mRNA? The sequence of amino acids is determined by the instructions from the genetic code in the DNA molecules which is passed on to mRNA. The genetic code is carried as a sequence of 'codewords' which are transcribed to mRNA. Each 'codeword' is made up of 3 bases and is called a codon. There are 64 different codons: One start codon which always codes for the amino acid methione (Met). Three stop codons which do not code for an amino acid. This triplet of bases is the basis of the genetic code as a gene is made up of a group of codons that code for the synthesis of one protein. The order of codons will therefore determine the sequence of amino acids which will determine which protein is made. The mRNA binds to the ribosome at the start (first) codon. The codons of the mRNA act as a template (pattern) that determines the order in which amino acids are linked. Translation of RNA to Proteins This stage of protein synthesis occurs in the ribosomes in the cytoplasm of the cell. It is the process by which a specific protein is formed from a chain of amino acids due to the sequence of codons on an mRNA strand which, in turn, was coded by the DNA. What is the role of tRNA? There are at least 64 different tRNA molecules, one for each of the 64 different mRNA codons. Each tRNA molecule has an amino acid on one end and a sequence of 3 bases on end known as anti- codons. These do not code for an amino acid. Instead, it allows tRNA to bind to the mRNA molecule long enough for the amino acid which it is carrying to form a peptide bond with the amino acid next to it to form a chain. This is important so that tRNA can deposit the correct amino acid in the correct place. Created by Ms. C.R. Els Page 9 Translation of RNA to proteins occurs in the following steps: After leaving the nucleus, the mRNA molecule attaches to a ribosome at the start codon. This start codon acts as a signal to begin the process of protein synthesis. The ribosome begins to read the mRNA strand one codon at a time. In the cytoplasm, there are free molecules of tRNA. The tRNA molecules bind with their specific amino acids in the cytoplasm and bring them to the mRNA molecule on the ribosome. The triplet of bases (anticodon) on each tRNA molecule pairs with a complementary triplet (codon) on the mRNA molecule. Two tRNA molecules fit onto the ribosome at any one time, bringing the amino acid they are each carrying side by side. A peptide bond is then formed between the two adjacent amino acids. This process continues until a ‘stop’ codon on the mRNA molecule is reached. This acts as a signal for translation to stop and at this point the amino acid chain coded for by the mRNA molecule is complete.. This amino acid chain then forms the final polypeptide (protein) and is released from the ribosome. What is the role of rRNA? rRNA is the most common form of RNA in the cell. It makes up the ribosomes. It moves from codon to codon, reading the code. It therefore plays a major role in controlling the process of protein synthesis. Using mRNA Codons to Determine the Sequence of Amino Acids Each mRNA codon corresponds to one of 20 different amino acids. You will be given the codons and corresponding amino acids in a table or on a wheel. You need to know how to use the table and the wheel to determine the sequence of amino acids formed from a set of mRNA codons. Created by Ms. C.R. Els Page 10 How Do Antibiotics Interfere With Protein Synthesis? Antibiotics are pharmacological drugs used to treat bacterial infections. They do this by interacting with bacterial ribosomes and inhibit their function of protein synthesis. If bacteria cannot produce proteins, they will not be able to make new cells to spread the infection. Different antibiotics target different stages of the mRNA translation so antibiotics can be changed if bacteria become resistant to a specific antibiotic. Genetic Code Summary The genetic code for the synthesis of proteins is carried on one strand of DNA. The sequence of the nitrogenous bases A, G, C and T forms the basis of this code. A group of three consecutive nitrogenous bases on DNA is known as a base triplet. This base triplet is complementary to an mRNA codon. One mRNA codon codes for one amino acid. Therefore the sequence of the base triplets on DNA determine the sequence of codons on mRNA which in turn determines the sequence of amino acids and the type of protein produced. A group of base triplets that code for the synthesis of one protein is a gene. Proteins determine the characteristics of an organism. These characteristics include structure and functioning. The genetic code is a universal code for all living organisms including viruses and bacteria. Complete the Protein Synthesis Worksheet Practice Exercise Unit 1 Question 11 -13 Page 1.49 - 1.50 Created by Ms. C.R. Els Page 11  Mutations Key Concepts: What a Mutation is, Chromosome Mutations, Gene Mutations, Substitution, Deletion, Insertion Page 1.12 - 1.13 What Is a Mutation? A mutation is any alteration in the genetic makeup/code of an organism. This means that there is a change in the sequence of nucleotides. Mutations may occur by chance spontaneously or as a result of mutagens. Mutagens are physical or chemical agents that cause mutations. Examples of mutagens include: Environmental factors such as sunlight, radiation and smoking Mutagenic chemicals such as formaldehyde Viruses and microorganisms Not all mutations are hereditary. Only mutations that occur in sex organs and sex cells during gametogenesis are inherited. Gametogenesis is the process by which gametes (sex cells) are produced in sex organs. There are 2 types of mutations: Chromosome mutations/ chromosome aberrations Gene mutations Chromosome Mutations/ Chromosome Aberrations A mutation that occurs when meiosis does not progress normally. These mutations may result in a change in the number or structure of chromosomes. This will be covered in more detail in meiosis. Gene Mutations A gene mutation occurs as a result of a change in the nucleotide sequence in the DNA molecule. Gene mutations are therefore small localised changes in the structure of DNA strands. Consequently, the code for protein synthesis changes and results in the formation of a faulty protein or even no protein at all because: Mutated DNA causes an alteration in mRNA Individual codons are affected The type of amino acid collected changes and therefore the protein changes Gene mutations can occur during: DNA replication Transcription of DNA to mRNA Crossing over during Prophase I of meiosis There are 3 types of gene mutations: Substitution - where one nucleotide is exchanged for another Insertion - where one or more extra nucleotides are added to the DNA molecule Deletion - where one or more extra nucleotides are removed from the DNA molecule Gene mutations can be classified as point mutations or frameshift mutations: Point mutations are changes which involve a single nucleotide. Frameshift mutations are changes which have a knock-on effect by changing the groups of codons further on in the DNA sequence. Created by Ms. C.R. Els Page 12 Substitution Mutations A gene mutation where one nitrogenous base is replaced by another. Only one nucleotide will be affected, therefore only a single codon will be altered and potentially only a single amino acid may change. Unlike an insertion or deletion mutation, a substitution mutation is a point mutation. So it will only change the amino acid for the codon in which the mutation occurs. It will not have a knock-on effect. Insertion Mutations A gene mutation where one or more nitrogenous bases are inserted. This means that one or more nucleotides are inserted, therefore one or more codons will be altered and therefore one or more amino acids may change. It is a frameshift mutation which has a knock-on effect by changing the codons further on in the DNA sequence. Deletion Mutations A gene mutation where one or more nitrogenous bases are lost. This means that one or more nucleotides are removed, therefore one or more codons will be altered and therefore one or more amino acids may change. It is a frameshift mutation which has a knock-on effect by changing the codons further on in the DNA sequence. Practice Exercise Unit 1 Question 15 Page 1.50 - 1.51 Created by Ms. C.R. Els Page 13  Application of DNA Technology Key Concepts: DNA Profiling/Fingerprinting, The Role of PCR in Fingerprinting, Uses of DNA Profiling, Views for and Against DNA Profiling/Fingerprinting, Ethics of obtaining DNA Samples Page 1.13 - 1.14 DNA Profiling/Fingerprinting Scientists are able to extract DNA from human body cells. DNA is prepared, arranged and a ‘barcode’ pattern is obtained. The pattern of the bars coincides with the sequence of base pairs that a person inherits from their parents. This ‘barcode’ is known as a DNA profile or as a DNA fingerprint. Different people have basically the same genetic material in their cells. These differences and variation between individuals are due to differences in the highly variable, non- coding DNA. Each individual has their own unique DNA profile. Except for identical twins who have the same DNA profile. The Role of Polymerase Chain Reaction (PCR) in Fingerprinting Biological evidence samples often do not contain sufficient DNA for testing. Biological evidence includes skin, blood, saliva, semen or hair. The Polymerase Chain Reaction (PCR) is a technology that can make multiple copies of a sample of DNA to millions of DNA segments. The DNA segments may be used for DNA fingerprinting. PCR simply replicates DNA in a test tube. It produces multiple copies of DNA from a small sample of DNA. It is vitally important in DNA fingerprinting as it ensures that there is enough DNA for testing. Created by Ms. C.R. Els Page 14 Uses of DNA Profiling DNA profiling can be used for the following: To determine the probability of inheriting a genetic disease/condition. To determine the cause of a genetic disease/ condition. To establish the compatibility of tissue types for organ transplant. The more nitrogenous base pairs the tissues have in common, the less likely it is for the body to recognise the transplanted tissue as foreign. Therefore it will be less likely that the body initiates an immune response. There is a lower risk of the transplanted tissue being rejected. To identify crime suspects in forensic investigations. The crime scene sample is definitely from suspect 2 because the barcode patterns indicating the nitrogenous base sequences are identical. As a proof of paternity or maternity. From the above data, it is clear that Dad 2 is the child’s biological father as they have the highest number of bands in common with the child. Created by Ms. C.R. Els Page 15  Views for and Against DNA Profiling/Fingerprinting For DNA Profiling Against DNA Profiling Establish proof of paternity of a child Inaccuracy of the DNA profiling leads to errors Trace lost relatives/separated siblings Human error in interpretation of the results Data may be used to discriminate against an ill Identify a missing person person DNA profiling is expensive so those who cannot Identify remains of victims of wars/accidents afford to pay for the cost will not have access to it Determine the probability of inheriting genetic Forensic labs do not always conform to uniform disorders/conditions standards Treating genetic disorders/conditions DNA samples may be planted at a crime scene Solving criminal cases in forensics Small samples of DNA may be identical in suspects Ethics of Obtaining DNA Samples There are ethical issues associated with obtaining DNA samples: Individuals must provide informed consent before their DNA can be collected. This means they should be fully aware of what the sample will be used for, the risks involved, and their rights regarding the data. It is unethical if DNA samples are obtained illegally without an individual’s consent. DNA contains highly personal and sensitive information. Ensuring the privacy and confidentiality of this information is crucial. Unauthorised access or breaches could result in confidential genetic information being accessed from public genome databases without an individual’s knowledge. This violates a person’s right to privacy. Access to DNA data could lead to discrimination or stigmatisation as the data may be abused by criminals or corrupt individuals. There is debate on ownership of DNA stored in DNA databases. Some claim that an individual should keep ownership of their DNA sample as it is highly personal and sensitive. Others claim that the institutions who have collected the sample with permission from an individual should have ownership of that DNA sample as it is stored in their database. Practice Exercise Unit 1 Question 16 - 19 Page 1.51 Created by Ms. C.R. Els Page 16