L2 - DevPsych

• Nature - the most important role in bringing about that feature
• • Nurture environment is most significant in shaping the way we are

   
• Ø  Polygenic - a result of many genes
• • Ø  Multifactorial a result of many factors, both genetic and environmental

   
• ·        There is a bidirectional interplay:

  Environment affects the expression of genes just as genetic predispositions can impact a person's potentialS Gottie), 1998, 2000. 2002)
• ·        Environmental circumstances can trigger symptoms of a genetic disorder.

  E.g. Diathesis-Stress Model of Psychological Disorders

   
• Heritability - a statistic that represents proportion of phenotypic variance that is due to genetic differences
• ·        Intelligence is inherited; in a person's genetics
• ·        Environment plays a significant role in a person's mental ability.
• Human Genome Project -  is an internationally funded effort to map the locations of human genes and understand the role these genes play in development, health, and illness.
• Genes are segments of chromosomes vary in length
• 46 strands of a chemical substance called DNA contained in the nucleus of each human cell
• Monozygotic or identical twins - occur when a single zygote or fertilized egg split apart in the first two weeks of development
• Dizygotic or fraternal twins - Two eggs or ova are released and fertilized by two separate sperm
• Our genotype is the genetic complement, coded in DNA inherited from our parents
• ·        The expression of those genes in behavioral traits that we can measure is called our phenotype.
• ·        Some genes are dominant: they 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.
• ·        No two people have identical genotypes except identical twins.
• ·        Sometimes dominant gene does not entirely suppress the recessive gene; this is called incomplete dominance
• ·        Chromosomal abnormality occurs when a child inherits too many or too few chromosomes.
• ·        If the abnormal number occurs on pair 21 or 23, individual may have certain physical or other abnormalities (e.g. Trisomy 21 or Down Syndrome).
• ·        When the abnormality is on pair #23, the result is a sex-linked chromosomal abnormality.
• ·        Most of the known genetic disorders are dominant gene-linked.
• §  Cases per birth - Sex-Linked Chromosomal Disorders: The disorder occurs on chromosome pair #23 or the sex chromosomes.
• §  1 in 2,500 females - Turner Syndrome is caused when all or part of one of the X chromosomes is lost before or soon after conception due to a random event. The resulting zygote has an XO composition. Turner Syndrome affects cognitive functioning and sexual maturation in girls. Infertility and short stature may be noted
• §  1 in 700 males - Klinefelter Syndrome is caused when an extra X chromosome is present in the cells of a male due to a random event. The Y chromosome stimulates the growth of male genitalia, but the extra X chromosome inhibits this development. The male can have some breast development, infertility, and low levels of testosterone.
• §  1 in 10,000 - Huntington's Disease is a condition that affects an individual's nervous system. Nerve cells become damaged, causing various parts on the brain to deteriorate. The disease affects movement, behavior, and cognition. It is fatal and occurs at midlife.
• §  1 in 250 - Tourette Syndrome is a tic disorder which results in uncontrollable motor and vocal ticks as well as body jerking.
• §  1 in 15,000-40,000 - Achondroplasia is the most common form of disproportionate short stature. The individual has abnormal bone growth resulting in short stature, disproportionately short arms and legs, short fingers, a large head, and specific facial features.

   
• §  1 in 500 Black births 1 in 36,000 Hispanic births - Sickle Cell Disease (SCD) is a condition in which the red blood cells in the body are shaped like a sickle (like the letter C) and affect the ability of the blood to transport oxygen. Carries may experience some effects, but do not have the full condition.
• §  1 in 3,500 - Cystic Fibrosis (CF) is a condition that affects breathing and digestion due to thick mucus building up in the body, especially the lungs and digestive system. In CE, the mucus is thicker than normal and sticky.
• §  1 in 10,000 - Phenylketonuria (PKU) is a metabolic disorder in which the individual cannot metabolize phenylalanine, an amino acid. Left untreated intellectual deficits can occur. PKU is easily detected and is treated with a special diet.
• §  1 in 400 1 in 300 American Jew is a carrier 1 in 20 French Canadians are a carrier - Tay Sachs Disease is caused by enzyme deficiency resulting in the accumulation of lipids in the nerve cells of the brain. This accumulation results in progressive damage to the cells and a decrease in cognitive and physical development. Death typically occurs by age 5.
• §  Fewer than 20,000 US Cases per year - Albinism is when the individual lacks melanin and possesses little to no pigment in the skin, hair, and eyes. Vision problems can also occur.

   
• ·        Behavioral Genetics is the scientific study of the interplay between the genetic and environmental contributions to behavior
• ·        Genotype-Environment Correlations refer to the processes by which genetic factors contribute to variations in the environment (Plomin, DeFries, Knopik. & Niederhiser, 2013).
• Passive

  ·        Children passively inherit the genes and the environments their family provides.

  Given both the genes and environmental encouragement
• Evocative

  ·        Social environment reacts to individuals based on their inherited characteristics.

  ·        E.g. Someone more outgoing or shy will affect how he or she is treated by others.
• Active

  ·        Individuals seek out environments & opportunities that support their genetic tendencies.

  ·        This is also referred to as niche picking.