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Biological and Environmental Foundations. Child Psychology Dennis H. Karpowitz. Genetic Foundation. Genotype – The total you Phenotype – The you we see. 23 Pairs of Chomosomes = 46. Genetic Code. Chromosomes - 23 pairs = 46 DNA (deoxyribonucleic acid) Genes Mitosis. DNA. The Sex Cells.
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Biological and EnvironmentalFoundations Child Psychology Dennis H. Karpowitz
Genetic Foundation • Genotype – The total you • Phenotype – The you we see
Genetic Code • Chromosomes - 23 pairs = 46 • DNA (deoxyribonucleic acid) • Genes • Mitosis
The Sex Cells • Gametes • Meiosis • Crossing over • Zygote - 23 pair = 46
Meiosis 46 Chromosomes in pairs Crossing over with the 2 inner-most pair members Pair chromosomes separate to form 2 sex cells of 23 chrom’s The duplicated chromosomes separate to form gametes, each with 23 single chromosomes Zygote, 46 chromosomes
Gender • 22 autosomes • Sex cromosomes 1. XX pair - female 2. XY pair- male Figure 1 Figure 2
Multiple Births • Dizygotic or fraternal twins • Monozygotic or identical twins
Patterns of Genetic Inheritance • Allele - two forms of each gene • Homozygous • Hetrozygous • Dominant & Recessive • Carrier • Modifier genes
E.g., Dominant & Recessive Genetic Disorders • Huntington Disease – Dominant • Fatal neurological disorder • Onset in middle adulthood, no treatment • PKU - Recessive gene • Cannot metabolize, amino acid phenylalanine • May cause retardation • Diagnosable at birth, preventable with diet
Dominant-Recessive Mode of Gene Inheritance, Illustrated by PKU
Genetic Patterns Continued • Codominance - Both alleles Influence • Sickle Cell Anemia – Blood disorder 1 in 500 African Americans • X-Linked Inheritance • Red-Green Color Blindness • Hemophilia • Genetic Imprinting • Praeder-Willi Syndrome, obesity + • Fragile X Syndrome, MR, Autism
Chromosomal Abnormalities • XYY Syndrome - Normal • XXX Syndrome - Verbal Abilities • XO - Spatial ability • Down Syndrome – Retardation • 21st Chromosome pair
Reproductive Choices • Genetic Counseling • Prenatal Diagnostic Methods • Ultrasound • Amneocentesis • Chorionic villi sampling • Adoption
Environmental Context • Family • Socioeconomic Status • Poverty
Environment Continued • Neighborhood • Schools • City Size
Larger Environment • Culture • Public Policy
Heredity & Environment Interact • Heritability • Kinship Studies • Concordance Rate • Range of Reaction • Interaction
Thought Questions • True or False: Genes determine for the most part who and what a child becomes. • True or False: Environmental influences really make the greatest difference in what a child becomes.