Forensic Genetics

FZ3011 Forensic Genetics SECTION A Short Tandem Repeat Polymorphisms Structure STRs, also known as microsatellites or simple sequence repeats (SSR), are 2-6bp DNA sequences tandemly repeated units flanked by unique sequence. They are usually between 100-300 bp long. They are classified based on the structure of the number of core repeats (base pairs): * Dinucleotide - 2 * Trinucleotide - 3 * Tetranucleotide - 4 * Pentanucleotide - 5 (Russell, 2006). They are also divided into categories depending on the type of repeats: * Simple - contain the exact same sequence and length with non-consensus alleles. * Compound - contain repeats of two or more adjacent simple repeats (non-consensus). * Complex - can be of several repeat blocks, varying sequences or intervening sequences. * Hypervariable - complex repeats with numerous non-consensus alleles, e.g. STR loci SE33 or ACTBP2. * Microvariants - contain alleles with incomplete repeat units, e.g. allele 9.3 at TH01 locus (Butler, 2005). Occurrence They are scattered throughout the genome and occur approx. every 10,000 nucleotides (Butler, 2005). Methods of Detection * Fluorescently labelled primers in PCR products are passed through Capillary Electrophoresis. As labelled PCR products migrate through the gel towards the anode on the laser they separate based on their size. Fluorescence is measured from exciting a

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  • Level: University Degree
  • Subject: Biological Sciences
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Genetics and environment: inseparable when discussing criminality.

Genetics and environment: inseparable when discussing criminality. Criminality is an ancient behaviour that appears with the civilization of the human being. Indeed even though one can measure aggression and violence in animals it could never be associated to criminality, for this concept involves the notion of law and moral that one transgresses. This is why criminality just as a concept could never be a purely biological outcome, because its roots are founded in society and thus in environment. When studying such a subject one must remember that we are discussing a social problem as well as a psychological problem and a biological one. Indeed we are going to discuss that different biological causes lead to criminality or predispose someone to it, then we will discuss the environmental factors. When discussing the genetics of criminality one must first specify what kind of criminality is in question. Indeed it would be hard to talk about the possible genetic inference in fraudulent behaviour. This is why we want to make a differentiation between violent criminality and non violent criminality. We are going to discuss the possibility of genes having some influence in criminality because "though the belief that single genetics defects produce criminal behaviour is untenable, behaviour is regarded as an emergent function of physical systems and brain activity which provides

  • Word count: 2794
  • Level: AS and A Level
  • Subject: Psychology
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Compare and contrast two explanations of depression.

Compare and contrast two explanations of depression. There are two types of depression, Bipolar and Unipolar both of which effect mood of the patient. Unipolar depression is where the person feels 'low' the majority of the time and have the following clinical characteristics: The emotional symptoms of unipolar depression are that the person feels intense feelings of guilt and a lack of enjoyment in activities that the individual previously enjoyed. Motivational symptoms can include difficulty in conducting actions as well as a lack of decision making. There are also cognitive and somatic symptoms which include negative thoughts and feelings of hopelessness (cognitive) as well as loss of energy, disturbance in weight and sleep (somatic). The clinical characteristics of Bipolar depression are also divided into four categories: Emotional, Cognitive. Somatic and motivational. Emotional characteristics are that if being euphorically happy then drastically changing into feeling of extreme sadness. The individual is also very irritable.Cognitive symptoms include an inflated self-esteem, racing thoughts and ideas as well as lack of attention however this may drastically change into feelings of hopelessness and dysfunctional thought. Somatic symptoms include decreased need of sleep as well as being fidgety and more talkative with rushed speech. Finally Motivational symptoms include

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  • Level: AS and A Level
  • Subject: Psychology
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Discuss The Biological Explanation for Depression and Biological Treatments for Depression

Discuss The Biological Explanation for Depression and Biological Treatments for Depression The biological explanation or the 'medical model' would favour the nature side of the nature nurture debate. This approach or explanation of dysfunctional behaviour / depression asserts that something in our biology or genetic makeup is the cause of the affective disorder depression. / dysfunctional behaviour such as depression. A number of things such as genetics (a predisposition), biochemical imbalance or even malformation of the structure of the brain are seen to contribute in their own ways to a person suffering from depression. Research has provided evidence to suggest that depression, a mood disorder, may be caused by other family members being diagnosed. Having a first degree relative (parent or sibling) with depression appears to be a risk factor for depression. Family studies such as Wenders select people who already depression. Twin studies also provide evidence of depression running in families. In Wenders study (1986) they looked at the biological relatives of adopted people who had been hospitalised for severe depression. The study found a much higher incidence of severe depression in those relatives than those of a non-depressed control group Wender concluded from this research that there is a significant genetic link between unipolar depression and suicide as there

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  • Level: AS and A Level
  • Subject: Psychology
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Genetics Research

Mitosis-The process of cell division producing daughter cells with exactly the same number of chromosomes as the mother cell. Self-bleeding, Human skin cells do this, they are Autosomes Interphase-period before Mitosis, where the cell gets ready for cell division. Interphase G1-Normal cell functions continue, the cell grows and protein synthesis occurs. Can last as little as 8-12 hours or as long as a few months. Skin cells take 8-12 hours. Interphase-Synthesis phase-Lasts 6-8 hours, the cell duplicates its chromosomes. Humans have 23 pairs of chromosomes, so after S phase there's 46 pairs of chromosomes. G2 Phase-lasts 2-5 hours, and protein synthesis occurs. Prophase- Longest phase. Chromosomes (made up of 2 sister chromatides that are connected by the centromere) coil up and become visible. The nucleus and the Nuclear membrane begin to disappear. Centrioles begin moving to the poles of the cell. Microtubules and Spindle Fibers begin to extend between the centrioles, and chromatins begin attaching to the spindle fibers/microtubules. Metaphase- Shortest phase, spindle fibers connect the centromere, of each of the 46 pairs of chromosomes, to the centrioles. Chromosomes also line up in the middle of the cell. Anaphase- Each chromosome pair splits up, pulling a chromatid with it, forming two daughter chromosomes (Once the paired sister chromatids separate from one

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  • Level: GCSE
  • Subject: Science
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abnormal psychology/depression

ABNORMAL PSYCHOLOGY PSY 03 WORD COUNT ,730 MAXINE JACKSON APRIL 2008 What is abnormal or normal? Abnormal literally means 'away from the normal'. Although it does not state what normal is. What is meant by normal differs over time and across cultures; it depends, to a certain extent on circumstances. Is something normal because the majority are doing it? During the Second World War thousands of innocent people were murdered in the name of Adolf Hitler. The Nazi's became the majority; however this does not make their behaviour normal. One way to decide what behaviour is normal is to consider how usual it is. In that case then, behaviour that is less common is abnormal. Society has standards to which they expect people to conform, this reflects on how people behave. These standards are classed as normal. Anyone who violates society standards is then abnormal. All societies are different and they expect different behaviour, because of this it is impossible to give a universal meaning of the word abnormal. It is difficult to class a person as abnormal or indeed normal, because of the differences in people to begin with. "A statistical norm is to do with a way of being, a quality or representation that is expressed or understood by many individuals. In other words, it is called average. High intelligence is as abnormal as low intelligence." J Cullberg (2006:09) Not

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  • Level: AS and A Level
  • Subject: Psychology
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Depression- Biological Explanations

Discuss biological explanation of depression. (25 marks) In order for depression to be diagnosed the person needs to show at least five of these symptoms everyday for a minimum of two weeks. These clinical characteristics for depression can be emotional symptoms; this can involve sadness, melancholy, self-involvement, guilt and even thoughts of suicide. Another characteristic could be a lack of motivation including passivity, loss of interest and energy. The person could also have cognitive problems such as thoughts of hopelessness, pessimism and lack of self-esteem. Finally there can be somatic symptoms such as loss or increase of appetite and weight, and sleep disturbances. Depression is a mood disorder which can have different variations; Unipolar disorder is most common and most severe form of depression and bipolar disorder is where the condition occurs in episodes of depression, periods of normality and periods of mania. This can be caused genetics which can predispose the individual to the disorder. Furthermore we would expect to find that relatives have similar chances of developing the disorder. Evidence from this can come from twin studies; MZ twins share 100% of their genes whereas DZ twins only have 50%. If genes are to be a facto in depression we would expect a higher number of MZ twins to share the disorder. One study based on nearly 200 pairs of twins found

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  • Level: AS and A Level
  • Subject: Psychology
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Genetics NOTES

Cells - Cells are basic units of what organisms are made up of - The shape and size of cells are related to their functions - Bacteria is a DNA that is not encapsulated by a membrane/nucleus - Chromosomes contain information for processing the functions of cells - Proteins (meats) are broken down into amino acids. These are very important for the body development - Everything in the body is made up of protein - If there is an excess of protein the body excretes it - Proteins are used for movement and repairing memory - Cilia are tiny hairs outside the cell that help it to move and attract food Inheritance - Genetics: The study of hereditary and the variations of characteristics - Mendel is known as the "Father of genetics" because he was the first person to discover things which we now know as genes. He was a monk who experimented with pea plants - True-breeding plants are plants which consistently produce offspring the same as the parents for a particular trait - In genetics, a dominant trait is a gene that expresses its instructions whereas a recessive trait 'masks' itself even though it's present - Mendel concluded from his experiments that some dominant and recessive genes were preset in each of the F1 and F2 generation - Genes are made from de oxy ribonucleic acid (DNA) - Chromosomes are the structures in which genes are kept. They are long, coiled;

  • Word count: 1830
  • Level: International Baccalaureate
  • Subject: Biology
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Depression. There are several approaches to depression, two of which are psychological and biological.

Psychology Assignment: Depression Depression is a type of mood disorder affecting a person's emotional state of mind. Unipolar disorder classifies depression under a DSM-IVR system where a person will be diagnosed if they shows signs of intense sadness or apathy alongside four other symptoms which include difficulties sleeping, fluctuations in energy levels, feelings of guilt and inferiority. It's crucial that these symptoms are clearly causing distress and consistently present for two weeks or more. It is important to identify and characterise depression in order to diagnose and treat the disorder. There are several approaches to depression, two of which are psychological and biological. The first psychological approach is the psychodynamic theory pioneered by Freud. His explanation of depression stems from relationships in early childhood, also focusing on the power of the unconscious and how this force propels our behaviour. Freud observed similar symptoms between grief and depression thus reaching the conclusion that depression is an extreme reaction to loss, whether real or imagined. It is this perceived loss and the failure to acquire an effective way of dealing with such a loss early on that increases the likelihood of becoming depressed when faced with another perceived radical loss. There is an emphasis on unresolved feelings of hostility when loss has been

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  • Level: AS and A Level
  • Subject: Psychology
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Genetics Assignment

Anatomy & Physiology Genetics TASK 1 DNA is a nucleic acid formed from nucleotides. Individual nucleotides are comprised of three parts: a. Phosphoric acid (Phosphate H3PO4). This has the same structure in all nucleotides. b. Pentose sugar: These are of two types - Ribose (which occurs in RNA) and Deoxyribose (which occurs in DNA). c. Organic bases: There are four different bases which are divided into two groups - Pyrimidines - these are single rings with six sides, are cytosine and thymine in DNA. Purines - these are double rings comprising a six-sided and a five-sided ring, are adenine and guanine in DNA. The three components are combined by condensation reactions to give a nucleotide. By a similar condensation reaction between the sugar and phosphate groups of two nucleotides, a dinucleotide is formed. Continued condensation reactions lead to the formation of a polynucleotide. DNA is a double stranded polymer made up of two polynucleotide chains (known as a Double Helix), where the pentose sugar is always deoxyribose and the organic bases are adenine, guanine, cytosine and thymine, but never uracil. The amount of guanine is usually equal to that of cytosine and the amount of adenine is usually equal to that of thymine. It is in the form of a double helix whose shape is maintained by hydrogen bonds. Each chain has a sugar phosphate backbone on the outside

  • Word count: 4660
  • Level: AS and A Level
  • Subject: Science
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