Gregor Mendel - ?· where a monk named Gregor Mendel documented inheritance ... •An organisms actual…

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<ul><li><p>1</p><p>Let there be </p><p>PEAS ON EARTH!</p><p></p><p>Unit 5 Notes: Genetics</p><p> Modern genetics began in the mid-1800s in an abbey garden, where a monk named Gregor Mendel documented inheritance in peas</p><p> used good experimental design</p><p> used mathematical analysis</p><p> collected data &amp; counted them</p><p> excellent example of scientific method</p><p>Gregor Mendel</p><p>Pollen transferred from white flower to stigma of purple flower </p><p>anthersremoved</p><p>all purple flowers result</p><p> Bred pea plants</p><p> cross-pollinate true breeding parents</p><p> raised seed &amp; then observed traits</p><p> allowed offspring to self-pollinate&amp; observed next generation</p><p>?</p><p>self-pollinate</p><p>When bred to themselves will always produce </p><p>organisms with same phenotype.</p><p>EX. White bred to white always produces white; purple bred to purple </p><p>always produces purple.</p><p>When a flower pollinates itself. No new genes are </p><p>introduced.</p><p>Mendels workMendel collected data for 7 pea traits</p><p>Each of these </p><p>traits is </p><p>represented by a </p><p>specific allele on </p><p>a specific </p><p>chromosome.</p><p>Allele = genes </p><p>that determine a </p><p>specific trait.</p><p>Flower color</p><p>Seed color</p><p>Seed shape</p><p>Pod color</p><p>Pod shape</p><p>Flower location</p><p>Plant size</p><p>2ndgeneration</p><p>3:175%purple-flower peas25%</p><p>white-flower peas</p><p>Parents</p><p>100%1stgeneration(hybrids)</p><p>100%purple-flower peas</p><p>Xtrue-breeding</p><p>purple-flower peastrue-breeding </p><p>white-flower peas</p><p>self-pollinate</p><p> Some traits mask others purple &amp; white flower colors are separate </p><p>traits that do not blend purple x white = light purple</p><p> purple masked white</p><p> Dominant allele functional protein</p><p> affects characteristic</p><p> masks other alleles </p><p> recessive allele no noticeable effect</p><p> allele makes a non-functioning protein</p><p>homologouschromosomes</p><p>allele producing</p><p>functional protein</p><p>mutant allele </p><p>malfunctioning</p><p>protein</p><p>What did Mendels findings mean?</p></li><li><p>2</p><p> Difference between how an organism looks &amp; its genetics</p><p> phenotype</p><p> Form of the trait that gets expressedwhat you see</p><p> genotype</p><p> An organisms actual alleles</p><p>Explain Mendels results using</p><p>dominant &amp; recessive</p><p>phenotype &amp; genotypeF1</p><p>PX</p><p>purple white</p><p>all purple</p><p>Genotype vs. phenotype Environment effect on genes</p><p> Phenotype is controlled by both environment &amp; genes</p><p>Color of Hydrangea flowers </p><p>is influenced by soil pH</p><p>Human skin color is </p><p>influenced by both genetics </p><p>&amp; environmental conditions</p><p>Coat color in arctic </p><p>fox influenced by </p><p>heat sensitive alleles</p><p>Phenotype is a result of both genetics and environment.</p><p></p><p></p><p>Cold Environment</p><p>Warm Environment</p><p>Siamese cats that grow </p><p>up in a cold </p><p>environment are </p><p>darker</p><p>than those that grow </p><p>up in a warmer </p><p>environment.</p><p>Inheritance of genes On the chromosomes passed from Mom &amp; </p><p>Dad to offspring are genes</p><p> may be same information</p><p> may be different information</p><p>eye color</p><p>(blue or </p><p>brown?)</p><p>eye color</p><p>(blue or </p><p>brown?)</p><p>Remember how Meiosis separates the alleles into sex cells?</p><p>This separation is called the </p><p>Law of Segregation.</p><p>Effect of genes</p><p> Genes come in different versions - alleles</p><p> brown vs. blue eyes</p><p> brown vs. blonde hair</p><p> Alleles = different forms of a gene </p></li><li><p>3</p><p>Homozygous dominant = AA</p><p>Homozygous recessive = aa</p><p>Heterozygous = Aa</p><p>Tt</p><p>Bb</p><p>WwYy</p><p>rr</p><p>RR</p><p>Aa</p><p>AB</p><p>Ss</p><p>bb EeBB</p><p>aaXY</p><p>Genes affect how you look</p><p>X</p><p>BBbb</p><p>Bb Bb Bb Bb</p><p>Where did the blue eyes go??</p><p>X</p><p>Bbbb</p><p>Bb Bb bb bb</p><p>Why did the blue eyes stay??</p><p>X</p><p>BbBb</p><p>BB or Bb BB or Bb BB or Bb bb</p><p>Where did the blue eyes come from??</p><p> Genes come in versions</p><p> brown vs. blue eye color</p><p> Alleles (different forms of a gene)</p><p> Alleles are inherited separately from each parent</p><p> brown &amp; blue eye colors are separate &amp; do not blend </p><p> either have brown or blue eyes, not a blend</p><p> Some alleles mask others</p><p> brown eye color masked blue</p><p> People who have one recessive allele and one dominant allele are called CARRIERS (they carry the recessive allele, but do not express the trait)</p><p> Carriers can pass on allele to offspring </p><p>How does this work?</p><p>eye </p><p>color</p><p>(brown?)</p><p>hair </p><p>color</p><p>hair </p><p>color</p><p>eye </p><p>color</p><p>(blue?)</p><p> Paired chromosomes have same kind of genes but may be different alleles</p><p>gene</p><p>allele</p></li><li><p>4</p><p>Traits are inherited as separate units For each trait, an organism inherits </p><p>2 copies of a gene, 1 from each parent</p><p> a diploid organism inherits 1 set of chromosomes from each parent</p><p> diploid = 2 sets (copies) of chromosomes</p><p>1 from Mom</p><p>1 from Dad</p><p>homologous chromosomes</p><p>Making gametes</p><p>BB = brown eyes</p><p>bb = blues eyes</p><p>Bb = brown eyes</p><p>BB</p><p>bb</p><p>Bb</p><p> brown is dominant over blue</p><p> blue is recessive to brown </p><p>Remember meiosis!</p><p>B</p><p>B</p><p>b</p><p>b</p><p>B</p><p>b</p><p>Dominant = can mask others</p><p>Recessive = can be hidden </p><p>by others</p><p>How do we say it?</p><p>BB = brown eyes</p><p>bb = blues eyes</p><p>Bb = brown eyes</p><p>2 of the same alleles</p><p>Homozygous</p><p>2 different</p><p>Heterozygous</p><p>BB</p><p>B</p><p>B</p><p>bb</p><p>b</p><p>b</p><p>Bb</p><p>B</p><p>b</p><p>homozygous dominant</p><p>homozygous recessive</p><p>Punnett squaresBb (carrier) x Bb (carrier)</p><p>male / sperm</p><p>fem</p><p>ale</p><p> / e</p><p>gg</p><p>s</p><p>X</p><p>BB</p><p>Bb bb</p><p>BbB</p><p>b</p><p>B b</p><p>Punnett square practice.</p><p>Genetics vs. appearance</p><p> There can be a difference between how an organism looks &amp; its genetics</p><p> appearance or trait = phenotype</p><p> brown eyes vs. blue eyes</p><p> genetic makeup = genotype</p><p> BB, Bb, bb</p><p>2 people can have the same appearance but </p><p>have different genetics: BB vs Bb</p><p>Genetics vs. appearance</p><p>eye </p><p>color</p><p>(brown)</p><p>eye </p><p>color</p><p>(brown)</p><p>eye </p><p>color</p><p>(blue)</p><p>eye </p><p>color</p><p>(brown)</p><p>vs.</p><p>BB</p><p>B</p><p>B</p><p>Bb</p><p>B</p><p>b</p><p>How were these </p><p>brown eyes made?</p></li><li><p>5</p><p>Making crosses Can represent alleles as letters</p><p> flower color alleles P or p</p><p> true-breeding purple-flower peas PP</p><p> true-breeding white-flower peas pp</p><p>PP x pp</p><p>PpF1</p><p>PX</p><p>purple white</p><p>all purple</p><p>Punnett squares</p><p>Pp x Pp</p><p>P pmale / sperm</p><p>P</p><p>p</p><p>fem</p><p>ale</p><p> / e</p><p>gg</p><p>s</p><p>PP</p><p>75%</p><p>25%</p><p>3:1</p><p>25%</p><p>50%</p><p>25%</p><p>1:2:1</p><p>%</p><p>genotype</p><p>%</p><p>phenotype</p><p>PP Pp</p><p>Pp pp pp</p><p>Pp</p><p>Pp</p><p>1stgeneration(hybrids)</p><p>Aaaaah,phenotype &amp; genotypecan have different </p><p>ratios </p><p>Using Punnett Squares</p><p>Bb x Bbmale / sperm</p><p>fem</p><p>ale</p><p> / e</p><p>gg</p><p>s</p><p>X</p><p>BB</p><p>Bb bb</p><p>BbB</p><p>b</p><p>B b</p><p>A Punnett Square is a diagram used to identify possible combinations resulting from a mating.</p><p>This married </p><p>couple is </p><p>considering </p><p>having their first </p><p>baby.</p><p>The man is </p><p>heterozygous for </p><p>a disease. The </p><p>woman is also </p><p>heterozygous for </p><p>the disease.</p><p>The couple comes to you for counseling. They want </p><p>you to know the chances they will have a healthy baby.</p><p>You know that the disease they carry is a recessive </p><p>trait and that both parents are heterozygous.</p><p>RR Rr rrWhich of the above genotypes will you need to use?</p><p>Man x Woman</p><p>Rr RrRrR r</p><p>RR</p><p>r</p><p>r</p><p>RR rR</p><p>Rr rr?</p></li><li><p>6</p><p>Man x Woman</p><p>Rr RrR r</p><p>R</p><p>r</p><p>RR rR</p><p>Rr rr</p><p>Genotype %RR =Rr =rr = </p><p>25%50%25%</p><p>Phenotype %Healthy =Carrier =Diseased = </p><p>25%50%25%</p><p>The chance that the </p><p>couple will have a baby </p><p>that has the disease is </p><p>25%.Lets Practice!</p><p>Not-so-bad Traits determined by Simple Inheritance</p><p> Tongue rolling (dominant form)</p><p> Widows peak (dominant form)</p><p> Hitchhikers thumb (dominant form)</p><p> Freckles (dominant form)</p><p> Taste PTC (dominant form)</p><p> Cleft chin (dominant form)</p><p> Dimples (dominant form)</p><p>No major consequences for these inherited conditions!</p><p>Genetics Lab</p><p> Work with a lab partner at a station</p><p> Check out each others traits</p><p> Write answers on your own paper</p><p> PTC and Control papers go in trash, not in sink (this will get you detention)</p><p> Complete the lab on your OWN paper</p><p>Recessive Genetic Disorders</p><p> Must inherit two faulty genes (one from mom, one from dad)</p><p> Parents who do not express the trait, but pass it on are called CARRIERS (HETEROZYGOTES)</p><p> Traits can be deadly</p><p>Recessive Genetic Disorders</p><p> Cystic fibrosis</p><p> Any of 1000 different mutations of one gene found on chromosome 7</p><p> Buildup of chlorine produces thick mucus around organs and in lungs</p><p> Weakened immune system</p><p> Life expectancy: 35 years</p><p> Found mostly in Caucasians</p><p>Recessive Genetic Disorders Tay-Sachs</p><p> Mutation of one gene on chromosome 15</p><p> Lack of an enzyme</p><p> Buildup of lipids on nervous tissue and in brain</p><p> Symptoms vary, but include hearing loss and pain</p><p> Nerve cells die</p><p> Die youngmost do not live past 4 years old</p><p> European Jews</p></li><li><p>7</p><p>Recessive Genetic Disorders Phenylketonuria</p><p> Deletion of one gene on chromosome 12</p><p> Protein buildup (phenylalanine) </p><p> Kills nerve cells</p><p> Tested for at birth</p><p> Solution: diet restricting phenylalanine (found in diet foods)</p><p> All demographics</p><p>Most Common Allele</p><p>Dominant or Recessive</p><p> Because an allele is dominant does not mean</p><p> it is better, or</p><p> it is more common</p><p>Polydactyly</p><p>dominant allele</p><p>Either One!</p><p>Dominant Genetic Disorders</p><p> Only need one dominant allele for it to be expressed </p><p> Most not lethal</p><p> Polydactyly</p><p> Chromosome 7</p><p> Extra digits (fingers or toes)</p><p> All demographics 1/500 people have extra digits</p><p>Dominant Genetic Disorders</p><p> Huntingtons Disease</p><p> Additions to gene making it longer </p><p> Chromosome 4</p><p> Adult onset (30-50 years old)</p><p>Why is this bad?</p><p> Brain dies</p><p> Loss of muscle control, dementia, pain </p><p>HUNTINGTONS DISEASE: dominantly inherited disease</p><p>Man x Woman</p><p>Rr rr</p><p>R r</p><p>r</p><p>r</p><p>Rr rr</p><p>Rr rr</p><p>A man has Huntingtons disease. </p><p>He does not know this because </p><p>Huntingtons doesnt show </p><p>symptoms until later in life, after </p><p>children have been produced.His wife does not </p><p>have Huntingtons </p><p>and knows that it </p><p>has never been </p><p>diagnosed in her </p><p>family pedigree.</p><p>What are the </p><p>chances their first </p><p>born child will </p><p>have the disease?</p><p>Heterochromia </p><p> Dominant autosomal</p></li><li><p>8</p><p>Dihybrid Crosses = mating of two individuals involving two traits.NOT A BIG DEAL. YOU HAVE OVER 30,000 GENES THAT CODE FOR PROTEINSEACH ONE HAS A GENOTYPE---THATS A LOT OF LETTERS</p><p>Heterozygous for both traits: </p><p>AaBb x AaBb</p><p>AB Ab aB ab</p><p>AB</p><p>Ab</p><p>aB</p><p>ab</p><p>A = tall</p><p>a = short</p><p>B = brown hair</p><p>b = blond hair</p><p>Tall/Brown</p><p>Tall/blond</p><p>Short/Brown</p><p>Short/blond</p><p>Testcrossunknown x aa</p><p></p><p></p><p>R? rr</p><p>ello, my name is </p><p>Reginald.I am a </p><p>magnificent red canary.</p><p>I want to make de beautiful red beebies like me.</p><p>But I do not know my genetics. How can I know if my beebies</p><p>will be red?</p><p>Hi there handsome! My names Gloria </p><p>and Im a purely recessive white </p><p>gal.</p><p>Maybe I can help you with </p><p>a testcross!</p><p></p><p></p><p>R? rr</p><p>Dees TESTCROSS</p><p>What is it?</p><p>Hmm I think this TESTCROSS is a good idea. </p><p>Its when you cross an </p><p>unknown genotype with a </p><p>homozygous recessive.</p><p>If you get any homozygous recessive babies, you know you </p><p>carry the recessive gene!</p><p>TESTCROSS = a cross between any gene pair </p><p>and the homozygous recessive condition for </p><p>that trait.</p><p></p><p></p><p></p><p>R? rr</p><p>Eeetworked!</p><p>Now I know that I carry </p><p>the rare white gene!</p><p>Congratulations handsome!</p><p>Youre a carrier!</p><p></p><p></p><p>Im the jailbird.</p><p>Rr rrThe twins</p><p>Rr and RrRr Rr</p><p>Later that year the babies were born</p><p></p><p>R?R</p><p>r</p><p>What would be the genotype needed to testcross a </p><p>heterozygous purple-flowering pea plant?</p><p>a. PP</p><p>b. Pp</p><p>c. ppAny Questions??</p><p></p><p>Assignment:Punnett Square Practice Worksheet</p><p>;imgrefurl=;usg=__ncHGFwlGeXYEiY006g2PNOpWCKE=&amp;h=255&amp;w=285&amp;sz=40&amp;hl=en&amp;start=21&amp;um=1&amp;itbs=1&amp;tbnid=byfcyxw63Slz_M:&amp;tbnh=103&amp;tbnw=115&amp;prev=/images?q=red+canary&amp;start=20&amp;um=1&amp;hl=en&amp;safe=active&amp;sa=N&amp;;ndsp=20&amp;tbs=isch:1;imgrefurl=;usg=__ncHGFwlGeXYEiY006g2PNOpWCKE=&amp;h=255&amp;w=285&amp;sz=40&amp;hl=en&amp;start=21&amp;um=1&amp;itbs=1&amp;tbnid=byfcyxw63Slz_M:&amp;tbnh=103&amp;tbnw=115&amp;prev=/images?q=red+canary&amp;start=20&amp;um=1&amp;hl=en&amp;safe=active&amp;sa=N&amp;;ndsp=20&amp;tbs=isch:1</p></li><li><p>9</p><p>2007-2008</p><p>Beyond Mendels Laws</p><p>of Inheritance</p><p>Extending Mendelian genetics</p><p> Mendel worked with a simple system</p><p> peas are genetically simple</p><p> most traits are controlled by single gene</p><p> each gene has only 2 version</p><p> 1 completely dominant (A)</p><p> 1 recessive (a)</p><p> But its usually not that simple!</p><p>Incomplete dominance</p><p> Hybrids have in-between appearance</p><p> BLENDING RR = red flowers</p><p> rr = white flowers</p><p> Rr = pink flowers make 50% less color</p><p>RR Rr rr</p><p>RRWW or RR</p><p>RW or RR</p><p>Incomplete dominance</p><p>true-breedingred flowers</p><p>true-breeding white flowers</p><p>XP</p><p>100%</p><p>100% pink flowers</p><p>1stgeneration(hybrids)</p><p>self-pollinate</p><p>25%white</p><p>2ndgeneration</p><p>25%red 1:2:1</p><p>50%pink</p><p>Incomplete dominance</p><p>RW x RW</p><p>R Wmale / sperm</p><p>R</p><p>W</p><p>fem</p><p>ale</p><p> / e</p><p>gg</p><p>s</p><p>25%</p><p>1:2:1</p><p>25%</p><p>50%</p><p>25%</p><p>1:2:1</p><p>%</p><p>genotype</p><p>%</p><p>phenotype</p><p>RR</p><p>RW</p><p>RW</p><p>WW</p><p>25%</p><p>50%</p><p>Incomplete Dominance Punnett Squares</p><p>1. Mate one white snapdragon with one red snapdragon.</p><p>2. Mate one pink snapdragon with one red snapdragon.</p><p>3. Mate one red snapdragon with another red snapdragon.</p><p>4. Mate two pink snapdragons.</p><p>5. Mate two white snapdragons.</p></li><li><p>10</p><p>Codominance Equal dominance</p><p> Chickens</p><p> A black-feathered chicken is crossed with a white-feathered chicken. (checkered chickens)</p><p> All of the babies are white with black speckling.</p><p> Both white and black show up equally.</p><p>x =</p><p>Codominance Punnett Squares</p><p>1. Mate a checkered rooster with a checkered hen.</p><p>2. Mate a checkered rooster with a white hen.</p><p>3. Mate a black rooster with a checkered hen.</p><p>4. Mate a black rooster with a white hen.</p><p>More Codominance</p><p>x</p><p>Human Codominance Example Sickle Cell Disease</p><p> Alleles</p><p> Normal red blood cell (HbA)</p><p> Sickle red blood cell (HbS) 1 in 12 African Americans carry allele</p><p> If two HbS alleles are inherited (HbSHbS), a person will be fully affected by disease</p><p> Aches, pains, fever, swelling</p><p> Can be fatal</p><p>Sickle Cell Trait</p><p> If only one HbS allele is inherited (HbAHbS), the person has sickle cell trait</p><p> Produce both normal and sickle red blood cells</p><p> Usually not affected by the symptoms </p><p> IMMUNITY TO MALARIA</p><p> Sickle cell allele originated in West Africa where malaria is common</p><p> Malaria passed on by mosquitoes</p><p> Plasmodium (malaria) cannot set up residence in sickle red blood cell</p><p>;imgrefurl=;usg=__W1_WMTn9paRT0PGOqPy-YjdC1Ww=&amp;h=800&amp;w=648&amp;sz=230&amp;hl=en&amp;start=21&amp;um=1&amp;tbnid=fgip2tg1MDg-3M:&amp;tbnh=143&amp;tbnw=116&amp;prev=/;imgrefurl=;usg=__W1_WMTn9paRT0PGOqPy-YjdC1Ww=&amp;h=800&amp;w=648&amp;sz=230&amp;hl=en&amp;start=21&amp;um=1&amp;tbnid=fgip2tg1MDg-3M:&amp;tbnh=143&amp;tbnw=116&amp;prev=/</p></li><li><p>11</p><p>Sickle Cell Punnett SquaresREMINDER: HbA (normal) HbS (sickle)</p><p>1) Heterozygous male and homozygous recessive female. Phenotypic ratio and genotypic ratio.</p><p>2) Homozygous recessive male and homozygous dominant female. Phenotypic ratio and genotypic ratio.</p><p>3) Homozygous dominant male and heterozygous female. Phenotypic ratio and genotypic ratio.</p><p>Multiple Alleles</p><p> More than one allele to select from.</p><p>...</p></li></ul>


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