Heredity, Prenatal, and Birth

    Cards (48)

    • Nature
      Heredity plays the most important role in bringing about a feature
    • Nurture
      Environment is most significant in shaping the way we are
    • Almost all human features
      • Polygenic - a result of many genes
      • Multifactorial - a result of many factors, both genetic and environmental
      • Genetic make-up sets up a range of possibilities
      • Genes may or may not be realized depending upon one's environmental experiences
    • Environment affects the expression of genes
      Genetic predispositions can impact a person's potentials
    • Environmental circumstances can trigger symptoms of a genetic disorder
    • Heritability
      A statistic that represents the proportion of phenotypic variance that is due to genetic differences
    • Estimates of heritability of intelligence are 80% (Bouchard et al., 1990) and 50% (Plomin 1990, 1995)
    • Environment
      Plays a significant role in a person's mental ability, e.g. education, SES, nutrition, parents' behavior, alcohol use, criminal behavior, emotional adaptation, amount of time spent reading or even watching television (Flynn, 1992)
      • Genes are segments of chromosomes that vary in length
      • 46 strands of chemical substances called DNA are contained in the nucleus of each human cell
    • Understanding the role of genes in health and illness can bring about both harm and good (Weitz, 2007)
    • Monozygotic or identical twins
      Occur when a single zygote or fertilized egg splits apart in the first two weeks of development
    • Dizygotic or fraternal twins
      Two eggs or ova, are released and fertilized by two separate sperm
    • Genotypes
      The genetic complement, coded in DNA inherited from our parents
    • Phenotypes
      Our observable characteristics
    • Dominant genes
      Express themselves in the phenotype even when paired with a different version of the gene
    • Recessive genes
      Express themselves only when paired with a similar version gene
    • Incomplete dominance
      When a dominant gene does not entirely suppress the recessive gene
    • Most characteristics are polygenic - not the result of a single gene, but of several genes
    • Chromosomal abnormality
      Occurs when a child inherits too many or too few chromosomes
      • Most of the known genetic disorders are dominant gene-linked
      • Vast majority are not severe disorders
    • Behavioral Genetics
      The scientific study of the interplay between genetic and environmental contributions to behavior
    • Genotype-Environment Correlations
      Processes by which genetic factors contribute to variations in the environment
    • Genotype-environment interactions
      • Involve genetic susceptibility to the environment
    • Periods of Prenatal Development
      1. The Germinal Period
      2. The Embryonic Period
      3. The Fetal period
      • Prenatal development starts at conception
      • Zygote (fertilized egg) contains the combined genetic information from both parents
      • After five days of mitosis, there are 100 cells, which is now called a blastocyst
      • The embryonic period begins once the multi-cellular organism is implanted in uterine wall
      • The placenta is a structure connected to the uterus that provides nourishment and oxygen from mother to embryo via the umbilical cord
    • Sex Linked chromosomal disorder: The disorder occurs on chromosome pair #23 or the sex chromosomes
    • Turner syndrome is caused when all or part of one od the X chromosomes is lost before or soon after conception due to a random event
    • klinefelter Syndrom is caused when an extra X chromosome is present in the cells of a male due to a random event.
    • Huntington's Disease (heterozygous) is a condition that affects an individual's nervous system. The disease affects movement, behavior, and cognition
    • Touretter syndrome (heterozygous) is a tic disorder which results in uncontrollable motor and vocal ticks as well as the body.
    • Achondroplasia (heterozygous) fingersis the most common form of disproportionate short stature. Abnormal bone growth resulting in short stature, disproportionately short arms and legs, short finger, a large head, and specific facial features
    • Genotype Environment Correlations
      refer to the processes by which genetic 
      factors contribute to variations in the 
      environment (Plomin, DeFries, Knopik, & 
      Niederhiser, 2013).
    • After five days of mitosis, there are 100 cells, which is now called a blastocyst
    • Cephalocaudal development from head to tail 
    •  Proximodistal development from midline outward
    • Teratology: a study of factors that contribute  to congenital disabilities
    • Alcohol is one of the most commonly used teratogens, followed by Tobacco
    • Genes are segments of chromosomes that vary in length
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