PCB 3063General GeneticsLecture Notes Exam 1This set of notes is really long! If you want to find notes for a specific date (ex: 1/27) or topic(codominance), press Ctrl F on your keyboard (Command F for Mac users) and type in what youwant to find. It’ll search the document for whatever specific word/phrase you typed in and saveyou the time of scrolling through everything!--------------------Mon 1/6Gregor Mendel- 1866, founder of geneticsDiscovered inheritance patterns using pea plantLed to Mendelian Inheritance conceptsKaryotype- organized spread of all of an individual’s chromosomes, shows genetic abnormalitiesEx: Down Syndrome karyotype reveals three chromosome 21’sTypes of genetics fields: cytogenetics, molecular genetics, eugenicsHeredity- transmission of genesTrait- phenotype, expressed genesDomestication- human adoption of wild plant/animal speciesArtificial selection- human-led breeding, goes back to around 10,000-20,000 B.C.Not the same as environmental selection, which is naturalEx: Dog breedingCan lead to inbreeding which increases the risk of certain diseasesCell division stages:Interphase -> early prophase 1 -> mid prophase 2 -> late prophase 3Development from gametes to embryo:Gametogenesis -> fertilization -> cleavage -> gastrulation -> neurulation -> organogenesis -> birthGametogenesis- creation of gametesZygote- fertilized egg cellCleavage- cell splits down middleBlastula- hollow, many cellsGastrulation- gastrula (mouth/anus tube) formedOrganogenesis- creation of organsSickle-cell anemia- genetic disease, red blood cell is C-shaped rather than a round discCaused by error in creating proteinsMakes malaria less effectiveMore common in African-AmericansFruit flies- commonly used in genetics experiments due to short lifespan and easy reproductionGenotype- genes, coding within DNAPhenotype- how genes are expressed, appearance, abilitiesWed 1/8(Most information here probably won’t be on the exam either)Preformationism- ideas about genetics from 1600-1850Homunculus- tiny person thought to be tucked inside a spermHumors- Plato + Aristotle, organs like gall bladder made substances that passed to offspringSpontaneous generation- Pasteur, living things come from inanimate objectsLeave food outside -> bugs magically appear!Fixity of species- number of species has always been the same since the Earth was madeEpigenesis- egg + sperm -> embryoGamete- egg or sperm, reproductive cellGerm-Plasm theory- gametes hold heritable traitsCell theory- Schwann + Schleiden, proposed idea of cell as basic unit of lifeAll organisms made of cellsCells only come from other similar cells (or stem cells)Natural selection- Darwin + WallaceProkaryote- no nucleusEubacteria- true bacteriaArchaeaEukaryote- have nucleusAsexual division- one cell -> two clonesPlasma membrane- outside of animal cellNucleus- holds DNANucleolus- inside nucleus, makes ribosomesEuchromatinHeterochromatin- forms DNAMitochondria- makes energy in animal cellsChloroplasts- makes energy in plant cellsMitochondria + chloroplasts have dif DNA than that in nucleus!Believed that they used to be symbiotic bacteria that got absorbed into the cellRibosome- protein synthesisCentriole- organize microtubulesEndoplasmic Reticulum (ER)Chlamydomonas- single-celled algae, has dif mating types1N cell -> mating (2N) -> meiosis -> four 1N offspring cellsMulticellular Reproduction:1N cell -> fertilization -> 2N zygote -> S-phase -> two 2N cells -> mitosis ->embryo -> organsEmbryo also creates a germ line of cells for the reproductive organs that produce gametesKaryokinesis- partitions genetic materialCytokinesis- cytoplasm divides, volume changesRNA- transcripted DNA, codes for proteinSome code for germ cells (RNA removed -> organism sterile/infertile)Chromatin- DNA + RNA + proteinsDiploid- 2N, 2 copies of same chromosome, skin cellsHaploid- 1N, 1 copy of chromosome, sex cellsMicrotubule- stringy fibers in cell, attaches to DNA for cell divisionKinetochore- narrow spot on DNA where microtubule can attachChromosome- tightly wound strand of DNA, formed during cell divisionHumans have 23 pairs (chromosomes #1-23), or 46 individual chromosomesCan be either a single strand (looks like I) or two (looks like X)Has two arms: P-arm (petite) and Q-arm (larger)Sister chromatid- half of a chromosomeWhen chromosome is shaped like an X, is a single strand (I)Both sister chromatids held together with cohesinCentromere- part where two sister chromatids meetLike the center of an hourglassCheckpoints- cell makes sure to see that division is running smoothly, helps prevent cancerSpindle assembly checkpoint- microtubule spindles made correctly and ready to goIf a checkpoint fails, cell division stops Apoptosis- programmed cell deathHappens when a cell is defective and needs to be eliminatedCoded for in the genesHelps prevent cancer and other dangerous cell divisionCell Cycle:G0 -> G1 -> check -> S -> G2 -> check -> MitosisInterphase- non-dividing stage (anything that isn’t mitosis)G0- cell grows and maturesG1- preparing for mitosis, has 1 strand of DNA for a chromosomeG1/S checkpoint- ready to commit to mitosisS – DNA synthesis, doubled to prepare for halving the cell laterG2- has 2 strands of DNA for a chromosome (sister chromatids)G2/M checkpoint- ready to enter mitosisM- Mitosis, division for nonreproductive cellsFri 1/10Stages of Mitosis:Prophase (Poles)Bundle the DNA replicated in S-phase into chromosomes, centrioles move to polesPrometaphaseNuclear envelope dissolves, spindle microtubules grab chromosomesMetaphase (Middle)Chromosomes line up on metaphase plate in center of cellAnaphase (Apart)Chromosomes split into 2 sister chromatids, move to opposite ends of the cellTelophaseChromatids unravel, nuclear envelope forms againCytokinesisOriginal 2N cell divides into two 2N daughter cells (diploid -> diploid)Meiosis- reproductive cell divisionOriginal 2N cell divides into four N daughter cells (diploid -> haploid)Broken down into Meiosis I and Meiosis IIHomologous chromosomes – two of the same kind of chromosome (chromosome #1, 2, 3, etc)When chromosome is shaped like an X, is two of them (XX)Otherwise look like two strands side-by-side like in karyotype (II)Tetrad- two homologous chromosomes wind together into single structureSynatonemal complex- holds tetrad togetherChiasma- crossover point on tetrad where chromosomes overlapRecombination- gene shuffling, happens on chiasmaStages of Meiosis:Meiosis I – division 1Prophase I (Poles)Tetrads
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