Genetics and EpigeneticsDNA  RNA  ProteinsGene expression-Transcription: DNA partially unwinds RNA madeTranslation: RNA instructs ribosomes to produce amino acidsComplete ProteinDNA- sugar phosphate backbone, adenine/thymine, guanineProteome- proteins encoded and expressed by genomeGenes – proteins – cells – behaviorGenotype- genetic instructionsPhenotype- observable traitsGenomics- Nucleus of each human somatic cell contains 23 pairs of chromosomes (46 total)One from mother, one from father1-22 are autosomes,23 is sexual characteristicsGene Expression: genetic instructions converted into a feature of a living cellMitochondrial DNA (mDNA): originates from motherAlleles: alternative versions of particular geneHomozygous: two identical allelesHeterozygous: two different allelesDominant Genes: those that mask other gene effects; routinely expressedRecessive Genes: genes that are expressed only in absence of a dominant gene; routinely not expressedComplete Dominance: Only the dominant allele’s trait is expressed in the phenotypeIncomplete Dominance: The phenotypic expression of the dominant allele’s trait is only partialCodominance: The traits of both alleles of a gene pair are expressed completely in the phenotypeMeiosis and Crossing Over: planned varietyMutations: replication errorsSingle nucleotide Polymorphisms (SNPs):Genetic mutations- Can have positive, neutral, or negative effects. May be specific or wide-spreadSickle Cell Anemia- Negative effects: Poor oxygen capacity. Positive effects-Some protection against malaria.Chromosomal abnormality- down syndromeSex-Linked characteristicsHemophiliaColor-blindnessX-Chromosome inactivation- One x is silenced to equalize protein production in males and femalesEpigenetics- Environment can influence whether or not a gene is expressedViewed as a second codeDescribes how single genetic code produces cell differentiationExplains how single genome can code for many phenotypesDescribes how cells can go astray and produce diseasesEpigenetic mechanisms influence protein productionBlocks gene to stop transcriptionUnlocks gene to allow transcriptionHistone modification: DNA may unwrap or be stopped from unwrapping from the histoneDNA modification: Transcription of DNA into mRNA may be enabled or blockedmRNA modification: mRNA translation may be enabled or blockedChimeric Animals: genes & behaviors combined from two parent speciesKnock-In: functioning gene(s) inserted into animals cells and is expressedKnock-Out: Inactivation of a gene so that it is not expressedBrain Development3 perspectives on brain developmentbrain development  behaviorbehavior  brain developmenthormones genes experience injury  behavioral or brain development which can influence each otherNeural developmentZygote- fertilization to 2 weeksEmbryo- 2 to 8 weeksFetus- 9 weeks-birthGerm layersEctoderm: outer layer; becomes skin and neural tissueMesoderm: middle layer; becomes connective tissue such as ligaments, muscles, blood vessels, and urogenital systemEndoderm: inner layer; becomes many internal organsEarly Neural DevelopmentNeural Plate (3 weeks after conception). Thickened region of the ectodermal layer that gives rise to the neural tubeNeural Tube - Structure in the early stage of brain development from which the brain and spinal cord developStages of neural development1. Cell Birth- neurogenesis; gliogenesis2. Cell Migration3. Cell Differentiation4. Cell Maturation- dendrite & axon growth5. Synaptogenesis-formation of synapses6. Cell Death & Synaptic Pruning7. Myelogenesis- formation of myelinCell BirthSubventricular Zone- Lining of neural stem cells surrounding the ventricles in adultsProgenitor Cell- Precursor cell derived from a stem cell; it migrates and produces a neuron or glial cellNeuroblast and GlioblastNeurotrophic Factor- A chemical compound that acts to support growth and differentiation in developing neurons. May help keep certain neurons alive in adulthoodEpidermal Growth Factor (EGF)- Stem cell  Progenitor cellBasic Fibroblast Growth Factor (bFGF)- Progenitor cell  Neuroblast*Stem- progenitor- blast- specializedCell proliferation- Cells that will become neurons divide and multiply at the rate of 250,000 new cells every minute. Occurs in ventricular zoneCell Migration- Neurons move from ventricular zone outward to final location“Inside out” migration.Cell Differentiation- Neuroblasts and glioblasts become specific types of cells. Begins soon after migration. Essentially complete at birth, but maturation continues throughout adulthoodFilopodia: long, fingerlike extensions from growth cones of neuritesLamellipodia: flat, sheet like extensions from core of growth conesSynaptogenesis- Interaction with target cells influences the type of neurotransmitter released by the presynaptic cell. Movement of receptors to the synaptic site guided by chemical release by presynaptic and postsynaptic structuresCell Death and synaptic pruning-Brain produces extra neurons/ Excess neurons and synapses must be eliminated1.) Late or off-target neurons die2.) Organization refined3.) Synapses strengthened or weakened depending on firingCell Life and Death-Neurotrophins: chemical factors that influence the survival of a neuronApoptosis: programmed cell deathMyelinogenesis- Occurs in rostral direction starting with the spinal cord, then hindbrain, midbrain, and forebrain. Burst in myelination around the time of birth. Prefrontal cortex not completely myelinated until early adulthoodLight zones- fastDisorders of Brain DevelopmentNeural Tube Defects- Anencephaly, Spinal bifidaGenetic Disorders- Down syndrome, Fragile-X syndrome, PKUEnvironmental Toxins- Fetal alcohol syndromeNeural Plasticity- nervous systems ability to change1. Before birth and until maturation is complete2. During learning (LTP)3. Following injury and degeneration4. Stem cells- specialized cells5. Neurogenesis- new neurons in adult brainVision and Visual PerceptionVisible SpectrumThe Advantages of Light as a Stimulus- Electromagnetic energy is abundant and travels quickly in fairly straight linesThe Electromagnetic Spectrum- Range of energy visible to humans falls between 400 and 700 nanometersAbsorption, Reflection, and Refraction-Absorption and reflection determine colors we see. Air and water refract, or change the direction, of traveling waves of lightBrightness: Intensity of reflected light that reaches our eyesHue: Color of lightColor Mixing- Additive (light), Subtractive