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Genes are composed of DNA & are located on chromosomes http://news.nationalgeographic.com/news/bigphotos/5940588.html. Gregor Mendel is considered the “ Father of Genetics ”. http://www.payer.de/fundamentalismus/fund0229.gif. http://faculty.uca.edu/~johnc/mendel1440.htm.
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Genes are composed of DNA& are located on chromosomeshttp://news.nationalgeographic.com/news/bigphotos/5940588.html
Gregor Mendelis considered the“Father of Genetics” http://www.payer.de/fundamentalismus/fund0229.gif http://faculty.uca.edu/~johnc/mendel1440.htm
Alleles are the TWOalternate forms of a geneONE from each parent http://www.zo.utexas.edu/faculty/sjasper/images/14.3.gif
There are two loci illustrated below…One for flower color& another for stem length http://faculty.clintoncc.suny.edu/faculty/Michael.Gregory/files/Bio%20101/Bio%20101%20Lectures/genetics-%20genes/img021.gif
Mendel’slaw of segregation is illustrated during meiosis Ihttp://www.biology.iupui.edu/biocourses/N100/2k4ch9meiosisnotes.html
During meiosis II, sister chromatids separatehttp://www.biology.iupui.edu/biocourses/N100/2k4ch9meiosisnotes.html
Usually only one of the two alleles is expressed This expressed allele is known as the dominant allelehttp://library.thinkquest.org/C004367/media/mendel.gif
What do genes code for?http://www.nchpeg.org/dental/images/GENES.GIF
What are examples of proteins?http://www.cybered.net/content.asp?contentid=684
In guinea pigs, black coat color is dominantover white coat color http://pics.hoobly.com/full/bd553abb0b9e97f3ef883a9c01150055.jpg http://www.meerschweinchen.de/cavia/pict/SHa-2.jpg
TEST CROSShttp://www.saburchill.com/IBbiology/chapters03/003.html In mice, grey(G) is dominant over white(g). Therefore, the genotype for a grey mouse could be GG or Gg. How could we find out?
Dihybrid Crosshttp://www.gwu.edu/~darwin/BiSc150/One/genetics.htm • A dihybrid cross results in a phenotypic ratio of 9:3:3:1
Mendel’s Law of Independent Assortmenthttp://fig.cox.miami.edu/~cmallery/150/mitosis/c13x9independent-assortment.jpg
Independent Assortmenthttp://fig.cox.miami.edu/~cmallery/150/mitosis/sf9x5b.jpg
Incomplete Dominancehttp://fig.cox.miami.edu/~cmallery/150/mendel/c14x9incomplete-dominance.jpg How do you think the pink flower in the middle came to be?
Incomplete Dominancehttp://fig.cox.miami.edu/~cmallery/150/mendel/incomplete.htm Both dominant alleles (R& W)express themselves, with each producing proteins that contribute to flower color
Roan coat color is a mixture of red &white hairshttp://upload.wikimedia.org/wikipedia/commons/b/bc/Belgisk_hest.jpg
Blood Typeshttp://fig.cox.miami.edu/~cmallery/150/mendel/blood.htmhttp://gslc.genetics.utah.edu/units/basics/blood/images/ABObloodsystem.gif
Genes found on the SAMEchromosome are linked& usually inherited together http://nwcreation.net/images/chromosome.jpg http://www.harcourtschool.com/glossary/science/images/gr5/gene5.jpg
Crossing Overhttp://www.nicerweb.com/doc/class/bio1151/Locked/media/ch13/13_11CrossingOver_L.jpg
Crossing over can unlinklinked geneshttp://img.sparknotes.com/content/testprep/bookimgs/sat2/biology/0001/crossingover.gif
For humans, the sex of the child depends on whether the sperm cell (n) that fertilized the egg cell (n) carried an X or Y chromosome • Note, this is NOT necessarily the case for other organisms
Map of Human ChromosomesFundamentals of Anatomy & Physiology (5th Edition), Martini. (2001). Page 1096.
The X&Y Chromosomeshttp://www.ncbi.nlm.nih.gov/books/bv.fcgi?call=bv.View..ShowSection&rid=gnd.section.295
Hemophilia is a sex-linked disorder. The gene is on the Xchromosome. http://www.pathguy.com/lectures/hemophilia.jpg http://www.hemophiliagalaxy.com/patients/images/genetics4c.gif
Red-Green Colorblindness http://intro.bio.umb.edu/111-112/111F98Lect/colorblind/ http://www.csun.edu/~vceed002/biology/senses/vision_labs/2a.jpg
Muscular Dystrophy http://www.artmed.pl/gfx/scol1.jpg http://members.lycos.nl/guvennekes/hpbimg/mattie%20stepanek.jpg
Chromosome mutations can be detected through karyotype analysis
Nondisjunction results in gametes with the incorrect # of chromosomeshttp://fig.cox.miami.edu/~cmallery/150/mendel/c15x11nondisjunction.jpg
Down Syndromehttp://employees.csbsju.edu/hjakubowski/classes/ch331/dna/chromosomes2.gifhttp://www.dsamn.org/photogallery/photoAlbums/DSAMFaces/full/scan0033.jpg
Chromosome Mutations http://www.tokyo-med.ac.jp/genet/picts/xo&xxy.jpg http://cas.bellarmine.edu/tietjen/HumanBioogy/bills_developmental_abnormalities.htm
Turner’s Syndrome (XO) &Klinefelter’s Syndrome (XXY) ttp://cas.bellarmine.edu/tietjen/HumanBioogy/bills_developmental_abnormalities.htm http://www.mf.uni-lj.si/acta-apa/acta-apa-02-4/3.1.jpg
Other Chromosome Mutationshttp://www.tokyo-med.ac.jp/genet/picts/13&18.jpghttp://cas.bellarmine.edu/tietjen/HumanBioogy/Finished%20Images/gen09.gif
Polyploid Plantshttp://www.anselm.edu/homepage/jpitocch/genbios/24-13-Autopolyploidy-L.gifhttp://waynesword.palomar.edu/hybrids1.htm
UV radiation can cause gene mutations by altering DNAhttp://www.opt.pacificu.edu/ce/catalog/15719-GO/Fig%206.jpg
Discussion Questions • Do any classmates have the same number you have? • How many different combinations of the 5 traits are possible? How many combinations would be possible with 6 traits? • In terms of what happens during meiosis and fertilization, explain how all the various combinations of alleles are possible. • Why is it virtually certain that, except for identical twins, even offspring of the same parents will not be genetically identical? • Using your own key, list your 5 traits and the possible genotype(s) for each. Note that all the traits listed are recessive.