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Flashcards by Greg MacPherson, updated more than 1 year ago
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Created by Greg MacPherson
over 2 years ago
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| Question | Answer |
| Unit Two - Module 14 Behavioural Genetics: Predicting Individual Differences | Behavioural Genetics: Predicting Individual Differences |
| behavioural genetics | The study of the relative power and limits of genetics (heredity) and environmental influences on behaviour. |
| heredity | The genetic transfer of characteristics from parents to offspring. |
| environment | Every non-genetic influence, from prenatal nutrition to the people around us. |
| DNA deoxyribonucleic acid | The molecule that makes up the hereditary material in humans and almost all other organisms. Nearly every cell in a person’s body has the same DNA. Most DNA is located in the cell nucleus, but a small amount of DNA can also be found in the mitochondria. |
| The four nucleotide bases | Adenine (A) Guanine (G) Thymine (T) Cytosine (C) Adenine always pairs with Thymine and Cytosine always pairs with Guanine |
| gene | A gene is the basic physical and functional unit of heredity. Genes are made up of DNA. Most genes act as instructions to make molecules called proteins. However, some genes do not code for proteins. In humans, genes vary in size from a few hundred DNA bases to more than 2 million bases. |
| allele | Every person has two copies of each gene, one inherited from each parent. Most genes are the same in all people, but a small number of genes (less than 1 percent of the total) are slightly different between people. Alleles are forms of the same gene with small differences in their sequence of DNA bases. These small differences contribute to each person’s unique physical features. |
| chromosome | In the nucleus of each cell, the DNA molecule is packaged into thread-like structures called chromosomes. Each chromosome is made up of DNA tightly coiled many times. Humans have a total of 46 chromosomes (23 pairs) in each cell of their bodies with the exception of the egg cell in females and the sperm cell in males that only have 23. |
| autosome | The first 22 pairs of chromosomes in humans are called autosomes. |
| sex chromosome | The 23rd pair in humans is the sex chromosomes - females have two x chromosomes and males have one x chromosome and one y chromosome. |
| dominant gene | If the two alleles are different in a pair of genes, it will be the dominant one that is expressed. |
| recessive gene | A recessive gene will only be expressed when there is not a dominant gene. |
| genotype | Genotype refers to the actual genetic code for that gene - the pair of alleles - often expressed as a pair of letters. |
| phenotype | Phenotype refers to the observable physical trait that this gene codes for. |
| homozygous | Homozygous means that both alleles are the same. |
| heterozygous | Heterozygous means that the two alleles are different. |
| Examples of Dominant Gene Disorders | Huntington's Disease - a breakdown in the neurons of the brain Marfan Syndrome - a connective tissue disorder |
| Examples of Recessive Gene Disorders | Cystic Fibrosis - a disease of the respiratory and digestive tracts Sickle-Cell Anemia - a blood disorder Tay-Sachs Disease - a fatal neurological disorder Phenylketonuria (PKU) - toxic build up of phenylalanine |
| Examples of Chromosome Disorders | Down Syndrome (Trisomy 21) - an extra chromosome #21 Kleinfelter Syndrome - an extra X chromosome in a male (XXY) Turner Syndrome - a female missing one of her X chromosomes. |
| identical twins (monozygotic twins) | Develop from a single fertilized egg that splits. They share 100 percent of the same genes. |
| fraternal twins (dizygotic twins) | Develop from two separate fertilized eggs. Therefore, they are genetically no more similar than regular siblings. |
| Thomas Bouchard | An American psychologist known for his behavioural genetics studies of twins raised apart. |
| heritability | Heritability is the proportion of variation among individuals in a group that can be attributed to genes. It is important to remember that heritability refers to variation within a group. It DOES NOT refer to the impact of nature on an individual. |
| molecular behavioural genetics | Molecular behaviour genetics is the study of how the structure and function of genes interact with our environment to influence behaviour. |
| epigenetics | Epigenetics is the study of how your behaviours and environment can cause changes that affect the way your genes work. Unlike genetic changes, epigenetic changes are reversible and do not change your DNA sequence, but they can change how your body reads a DNA sequence. |
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