(Microsoft PowerPoint - Mendel\222s Genetics) - Jefferson County ...

2/5/2013Mendel’s GeneticsTransmission of characteristics from _______________________is parents to offspring called___________________.heredityThe science that studies how those characteristics are _________ passed on fromone generation to the next is called _____________.GeneticsWho was Gregor Mendel? A 19 th century Monk and Scientists who iscredited for being the Father of theGenetics branch of Science.Who was Gregor Mendel? --Discovered that Genes and Heredity determinewhat characteristics an organism will have, basedon Experiments with Pea Plants inhis garden.Mendel designed ____________ experiments using__________ Pea plants in the monastery gardenIn pea plants, the pollen normally joinssamewith an egg from the _______ plant(=_______________Self pollinating) so seeds haveONE parent“_________________”MENDEL’S PEA EXPERIMENTSMendel started his experimentswith peas that were_________________true breeding (or purebred)= if allowed toself pollinate_________________they would produceoffspring identical____________________to themselves.1

2/5/2013Mendel _________removed pollenmaking partsand _______ added pollen from _______ another plant.This allowed him to ______ cross-breed plantswith ______ differentcharacteristicsand ________studythe resultsA _____________________ specific characteristic is calleda ____________traitMendel ______________ studied 7 traits in peas.When Mendel _________ crossed PURE plants with 2 _________contrastingtraits: (EX: Tall crossed with short)He always found same pattern:1. ONLY ______ 1 trait __________ showed in the ____ F 1 generationBUT . . .2. ________ Missing trait ________ returned in the ____ F 2 generationin a ____ 3:1 ratioP 1____ generation(_________)parental____ F 1 generationfilial(______= offspring)___ F 2 generationWho was Gregor Mendel?Mendel decided that theremust be a _________________pair of FACTORSthat ________each control trait andthat _________one factormust be ableto _______ HIDE the other.We now know that Mendel’s________________ factors are genes carried onthe pair of________________Homologous chromosomesMendel’s 4 genetic Hypotheses 1. An individual has two copies of the gene – onefrom each parent.Mendel’s 4 genetic Hypothesizes 2. There are multiple versions of a Gene.--meaning that for a Gene that expresses a flowercolor, there may be Pink Color Genes, WhiteColor Genes, and Red Color Genes.--These different versions of the samecharacteristic are called Alleles.2

2/5/2013Mendel’s 4 genetic Hypothesizes 2. Genes/alleles can be Homozygous orHeterozygous.Mendel’s 4 genetic Hypothesizes Homozygous Alleles =2 of the same versionof an allele. Ex: having 2Brown Hair genesMendel’s 4 genetic Hypothesizes Heterozygous Alleles = having 2 different versionsof the gene/alleleat the same time.Mendel’s 4 genetic Hypothesizes 3. Alleles come in 2 Types: DominantGenes/alleles and Recessive Genes/alleles. Ex; having 1 Brown HairGene and 1 Blonde HairGene.Mendel’s 4 genetic Hypothesizes Dominant—”stronger gene” If the trait is Heterozygous (having 2 differentalleles), the Dominant gene will overpower theRecessive, and the trait appearance would bewhatever the Dominant Gene is.Mendel’s 4 genetic HypothesizesEx: If you carry 1 BlueEye Gene and 1 BrownEye Gene… the Brown is Dominant, and the Blue is Recessive:so your eye color would be Brown, even throughyou have a Blue Eye Allele.3

2/5/2013Mendel’s 4 genetic Hypothesizes Recessive—”weaker gene” The gene that would be “covered up” in thePresence of another Dominant Gene.Mendel’s 4 genetic Hypothesizes To have a recessive characteristic, such asBlonde hair, both of the 2 genes for haircolor MUST be the recessive Blonde Hairgenes.Mendel’s 4 genetic Hypothesizes 4. Principle of Segregation A. all characteristics have2 genes/alleles each. B. When Haploid Cells are created, each of these 2genes for all the characteristics of an organism areSegregated (separated) into their own HaploidCell—making Haploid cells with only 1 gene percharacteristic.Mendel’s 4 genetic Hypothesizes C. during Cell Fertilization(union between asperm/pollen cell andan unfertilized egg/seedcell) Each single,Haploid cell’s allelesare combined to makethe 2 alleles percharacteristic neededto express the trait.Mendel’s 4 genetic Hypothesizes When 2 different Haploid Cells combine, it makesa Fertilized Egg Cell or Zygote with 2 Alleles pertrait. Dominant andRecessive Gene ruleswill then determine theactual appearance ofthe organism.Phenotype vs Genotype--a Phenotype is the Observable APPEARANCE ofan organism’s genetic make-up determined by thetype of alleles the traits have (Homozygous-Recessive, or Dominant-Heterozygous)Ex; height, coloring, size,shape, ect4

2/5/2013Phenotype vs Genotype--A Genotype is the GENETIC MAKEUP of thatorganism, that translates into the Phenotype.Ex: Genotype of aBlonde Hair Trait: bb(Homozygous-RecessiveBlonde Alleles)5