Lecture 3Outline of Last Lecture I. Theories of Human Development: Crash CourseA. Grand TheoriesB. Emergent TheoriesOutline of Current Lecture II. Biological FoundationsA. The Genetic CodeB. Chromosomes, Cells, and SexIII. Patterns of Genetic InheritanceIV. Behavior Genetics ResearchA. FindingsB. Reaction RangeV. Genetic – Environmental CorrelationVI. Chromosomal AbnormalitiesCurrent Lecture Heredity and EnvironmentThe foundations of human development are heredity and environment. An organism’s unique genetic code is called a genotype and the way that the organism physically looks is called a phenotype. The human genetic code is made up of DNA. DNA: Deoxyribonucleic Acid, DNA carries the instructions for making specific proteins.Chromosomes: Chromosomes are found within the cell nucleus and store and transmit DNA.Genes: These are segments of DNA located along the chromosome that contain genetic information.DNA, Chromosomes, and Genes make-up the human genome, or the code for making a human. Each individualhas a unique code, but all humans share about 99.5% of their genes.Autosomes 22 pairs of chromosomes are NOT sex chromosomesSex Chromosomes 23 pair of chromosomes that determines sexXX=Female and XY=MaleGametes These are the sex cells (sperm and ova)Zygote Sperm and ova united, and will eventually form an embryo PSYCH 250 1st EditionIn relation to twins, fraternal twins are from two separate ova that were fertilized at the same time (often times women aged 35 and above will release two ova instead of one during ovulation) and two separate zygotes were formed. Fraternal twins share about 50% of their genes. However, identical twins are from a single fertilized zygote that divides into two individuals. Identical twins share 100% of their genes.Assisted Reproduction: A woman can take drugs to cause ovulation, usually of several ova at a time. If they are all fertilized, multiple births will occur.Each sex cell (gamete) has 23 chromosomes, so that when combined with the opposite gamete, the resulting human will have 46 chromosomes. Alleles: are two forms of each gene that appear at the same place on both chromosomes in a pair.Homozygous: Alleles from both parents are the sameHeterozygous: Alleles from each parent is differentThere are six Patterns of Genetic Inheritance: Additive Heredity, Dominant-Recessive, X-Linked, Incomplete Dominance, Genetic Imprinting and Polygenetic Inheritance.Additive Heredity: Some alleles are additive because their effects add up to influence the phenotype. When genes interact additively, the phenotype will reflect the contribution of each gene (Berger). This additive effect can be seen in traits such as hair curliness, height, and skin color.Dominant-Recessive: This pattern of inheritance occurs when one allele is more dominant (is more influential) than the other (the recessive allele). The dominant gene will control the characteristic. Ex: Brown eyes are causes by a gene that is dominant over blue eyes.X-Linked Heredity: refers to a gene carried exclusively on the X chromosome. If a male inherits an X-linked recessive from his mother, he will express that trait, because the Y chromosome from his father does not have an allele to counteract it. Women are more likely to carry these X-linked recessive traits, but less likely to express them.Ex: Red-green color blindness and hemophilia are X-linked recessive disordersIncomplete Dominance: both alleles, dominant and recessive are expressed, resulting in a characteristic that is an intermediate of both traits.Ex: Sickle-cell anemia is more prevalent among African AmericansGenetic Imprinting: means that genes function differently depending on which parent they came from. A chemical maker activates either the father or mother’s genes. Prader-Willi Syndrome and Angelman Syndrome are the best known examples of imprinting. Prader-Willi Syndrome comes from a deletion (removal of a small part of a chromosome) on the father’s chromosome 15. This syndrome results in the child being obese, slow-moving, and often angry. If this deletion occurs on the mother’s chromosome 15, the child will be thin and hyperactive.Polygenetic Inheritance: Most traits are polygenetic (affected by multiple genes) and are multifactorial. With this form of inheritance, genes and the environment interact to produce a complex trait.Ex: Personality, IntelligenceBehavior Genetics Research: the study into how certain genes play a role in shaping behavior. Researchers use various methods to study the role of how genes and environment coincide in shaping human behavior. One major finding was that while genes impact every characteristic of behavior, family structure parenting style canmodify these genes.Behavior Genetics Research has also concluded that:  Genes affect every aspect of human behavior. The non-shared environment is powerful Genes elicit responses from other people that shape development. People choose environments that “fit” with their genes – thus, genetic influences increase with age.Range of Reaction: refers to an individual’s genetically determined response to the environment.Ex: Children exposed to a highly enriched environment tend to have higher IQ scores compared to children who do not.There are three types of Genetic-Environment Correlations: Passive, Evocative, and Active.Passive Correlation: This refers to one in which the child has no control. Child is passive recipient of environment (commonly seen in early childhood, ex: active parent wants to live through their child so they make sure that they are always in sports). Evocative Correlation: Children evoke responses that are influenced by their own heredity and these responses serve to strengthen and reinforce the child’s original personality and style. Children come into the world as their own person (difficult temperament – elicits negative feedback, reinforces temperament)Active Correlation: Refers to that as children grow older, they are more likely to seek out environments that fit their genetic makeup according to personality traits, and behavior. Genes have been found to influence several disorders such as: Schizophrenia, Addiction (alcoholism), Nearsightedness, and Diabetes. However aside from genes alone, environment also plays a key role into the development of these disorders.Chromosomal Abnormality: different from the genetic-environmental correlations mentioned above. Chromosomal abnormality means that a