PSYC 2006: Foundations of Human Dev. Part 1: Heredity. September 19, 2013

Transcription

1 Foundations of Human Development Part 1: Mechanisms of Genetic Disorders is not destiny Mechanisms of Genetic Disorders Mechanisms of Genetic Material located in Chromosomes Chromosomes are made up of a Deoxyribonucleic acid (DNA) Molecule eedtys is not otdestiny Chromosomes Chromosomes--Four Key Points Four important points to remember 1. Number of chromosomes in each cell is important In humans there are 23 pairs 46 chromosomes Return 1

2 Chromosomes Chromosomes--Four Key Points 1. Number of chromosomes in each cell is important 2. Chromosomes are arranged in pairs Return Chromosomes Chromosomes--Four Key Points 1. Number of chromosomes in each cell is important 2. Chromosomes are arranged in pairs 3. Pairs 1 to 22 are called autosomes Pair 23 = sex chromosomes (X and Y) Females (XX); males (XY) Return Chromosomes Chromosomes--Four Key Points 1. Number of chromosomes in each cell is important 2. Chromosomes are arranged in pairs 3. Pairs 1 to 22 are called autosomes 4.Reproductive cells also called gametes The sperm and the egg Only have 23 chromosomes Created through meiosis Crossover of genes Reduction into single chromosome Return 2

3 Meiosis and Crossover Crossover of Genes KU7JnMQ&feature=endscreen Genes and the Production of Protein Genes Located at particular sites on chromosome Genes and the Production of Protein Genes Located at particular sites on chromosome Contain directions for making proteins Genes and the Production of Protein Genes Located at particular sites on chromosome Contain directions for making proteins Made up of DNA DNA = Dioxyribonucleic acid DNA video &feature=related 3

4 Genes and the Production of Protein Detail of DNA Molecule 4 Bases Adenine Cytosene Guanine Thymine 2 Base Pairs Cytosene Guanine Thymine Adenine Principles and Processes of Molecular Genetics The transmission of traits: A basic model The transmission of traits: A basic model Multiple forms of gene present at any gene s position Alleles One from each parent If same, then homozygous If different, heterozygous Heterozygous Alleles 3 possible outcomes Incomplete dominance Between the two extremes 4

5 Incomplete Dominance Heterozygous Alleles 3 possible outcomes Incomplete dominance Codominance Both characteristics expressed Codominance Heterozygous Alleles 3 possible outcomes Incomplete dominance Codominance Dominance Dominant characteristic expressed Dominance Exceptions to the rule Genes on the sex chromosomes XandYChomosomes Downloaded from: 5

6 Sex-Linked Disorders Sex-linked Traits Sex-Linked Disorders Examples Hemophilia Red-Green Colour Blindness Behavioural Genetics Methods of studying Genetic differences Adoption studies Child similar to adoptive family = Environment Child similar to biological family = Genetics Behavioural Genetics Genetics of Twins Methods of studying individual differences Adoption studies Twin studies 6

7 Twin Studies--An Example Twin Studies--An Example Is extroversion inherited? Take measure of extroversion Approaching stranger Find correlation between twins Monozygotic Dizygotic Adoptive Studies-- An Example Behavioural Genetics Methods of studying individual differences Adoption studies Twin studies Blended Families Blended Families Behavioural Genetics Results Initiated by Reiss et al. (1994) Sibling % Genes share in Type common Full 50% Half ~25% Step 0% 7

8 Behavioural Genetics Results Mechanisms of Genetic Disorders is not destiny Genetic disorders Sickle cell anemia Why do harmful alleles survive? If heterozygous, not harmful (maybe even helpful) E.g., Sickle cell anemia Mechanisms of Genetic Disorders is not destiny is not destiny Environment influences genetics Range of reaction 8

9 Range of Reaction is not destiny Genetics shape environment Niche picking Deliberately picking an environment that will allow best development according to genes Conclusions Genetics provide important framework for development Important to understand genetic link Environment also important Next: Prenatal Development and Childbirth 9