Notes Compilation Week 1
Notes Compilation Week 1 BIOL 1101 02
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This 5 page Class Notes was uploaded by smanske on Wednesday September 30, 2015. The Class Notes belongs to BIOL 1101 02 at University of Minnesota - Morris taught by Rachel M Johnson in Summer 2015. Since its upload, it has received 65 views. For similar materials see Fundamentals of GenEvoDevo in Biology at University of Minnesota - Morris.
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Clutch. So clutch. Thank you sooo much Sydney!!! Thanks so much for your help! Needed it bad lol
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Date Created: 09/30/15
Biology Notes Compilation Week 1: 9/29/15- 10/1/15 Gregory Mendel (1822-1884) o Grew up on a farm (breeding) o Became a monk (education) o Work was rediscovered in the early 1900’s How does inheritance work? o Two hypotheses: Blended—when two parental traits come together they blend irreversibly Particulate—the two parental traits will interact in the offspring but when the offspring reproduces the traits can be passed on separately Mendel used controlled cross-pollination with pea plants Parental Generation (G) wrinkled peas x round peas 1 Filial Generation (F1) all round peas Mendel self-fertilized the 1 generation 2 ndFilial Generation (F ) round and wrinkled peas 2 3:1 ratio round to wrinkled This experiment proved the particulate theory Punnett Square Round peas: RR R R Wrinkled peas: rr Rr Rr r Rr Rr r F1generation of all round seeds Mendel concluded that round seeds were the dominant trait and wrinkled seeds were recessive. Gamete—sex cells made during meiosis, haploid cells Genotype—your genetic make-up Phenotype—the expression of your genetic make-up o Phenotype does not always equal genotype Genes—hereditary factorsphysical locations with our DNA Alleles—different versions of a gene o Ex.) Round and wrinkled peas Gene: shape determining protein Alleles: Round Wrinkled Homozygous—two alleles for a gene are the same o Ex.) RR and rr Heterozygous—two alleles for a gene are different o Ex.) Rr and Tt Particulate Theory o Law of Segregation—during reproduction (meiosis), two copies of a gene will separate and get passed on individually to the gametes o Dihybrid Cross P: Round, yellow x Wrinkled, green RR, YY rr, yy F1: Rr, Yy Round, yellow F2: RY ry Ry rY RY RRYY RrYy RRYy RrYY ry RrYy rryy Rryy rrYy RRYy Rryy RRyy RrYy Ry RrYY rrYy RrYy rrYY rY Phenotype: 9:3:3:1 9/16 Round, yellow 3/16 Round, green 3/16 Wrinkled, yellow 1/16 Wrinkled, green Law of Independent Assortment—alleles of different genes will assort independently during meiosis o Chromosomes from mother and father will mix and then assort separately during meiosis Test Cross—breeding with a recessive to find an unknown genotype o Ex.) p p p p P Pp Pp P Pp Pp Pp Pp ? Two possible P ?p ?p options: p p P P P p p p p p Example 1: p p o Purple (PP, Pp) vs Yellow (pp) o Smooth (SS, Ss) vs Wrinkled (ss) o How would you set up a test cross for a cob with smooth, purple seeds? You would breed it with a cob that has yellow, wrinkled seeds (ppss) Dominance o Complete Dominance—when the dominant allele completely takes over Results in only the dominant allele being visible Ex.) PP Pp where “P” is dominant o Incomplete Dominance—no dominant allele or recessive allele they blend together in the phenotypes Ex.) Snapdragons: Red x White = Pink o Co-Dominance—intermediate phenotype no dominant or recessive alleles, but you see both alleles presented separately Ex.) Red x White = Red and White Epistasis: Interactions Among Genes o Cat fur colors are determined by multiple genes Epistasis—two or more genes affecting one phenotype White gene—two alleles, Ww, where “W” is completely dominant o “W” is epistatic to other alleles “W” allele takes over Piebald gene—two alleles, Ss, where “S” is incompletely dominant o SS white patches more than 50% but less than 100% o Ss white patches less than 50% o Ss no white patches, solid color Black gene—three alleles (B, b, and b’) complete dominance where B>b>b’ o BB, Bb, Bb’ produces black color o bb, bb’ produces dark brown color o b’b’ produces “cinnamon” color Diluted gene—two alleles, Dd, affect phenotypes of black and orange gene with complete dominance o DD, Dd not diluted o Dd diluted orange and black Orange gene—sex-linked, located on X chromosome o XX cat female O O X X orange X X tortishell color (black and orange) X X not orange o XY cat Oale X Y orange X Y not orange Hemizygous—sex-linked male gene that cannot be hetero- or homozygous In-Class Problem o A child and her mother both have blood type O. For a man to be excluded as a possible father, what blood type must he have? A B Genotype I I ; Type AB blood o Is it possible for this kind of evidence to prove that any man is the father? No, the father can have type A, B, or O blood. Pedigrees o Look at family history o Look at inheritance pattern for one trait/phenotype o Key: Females are represented by “O” If the “O” is filled in, then the female is affected by the gene Males are represented by If it’s filled in, then the male is affected Mating is represented by a line between an O and Mating between relatives is represented by a double line Tracking Inheritance o Caused by dominant or recessive allele Linked Genes o Does the Law of Independent Assortment always apply? No o Ex.) Body color: Gray, BB or Bb Black: bb Wing size: Normal, VgVg or Vgvg Small: vgvg P: BbVgvg x bbvgvg BVg, Bvg, bVg, bvg bv F1: Genotypes: BbVgvg, Bbvgvg, bbVgvg, bbvgvg Phenotypes: black, normal; black, small; gray, normal; gray, small Expected Ratio: 1:1:1:1 Thomas Morgan (1866-1945) o Discovered the crossing over of monologous chromosomes during meiosis B and Vg alleles appear on the same chromosome o Law of Independent Assortment no longer applicable Crossing over does not always occur. o No crossing to get genotypes BVg or bvg Occurs less frequently Law of Independent Assortment (continued) o Does not always apply! If two genes are on the same chromosome then the law will not apply Mendel’s traits were all on different chromosomes Crossing Over—can occur between homologous chromosomes during meiosis Linked Genes—genes that are on the same chromosome Unlinked Genes—genes that are on different chromosomes o Ex.) YY or Yy brown body color yy yellow body color WW or Ww red eyes ww white eyes P: YYww x yyWW F1: YyWw x yyww F2: Yw yW YW yw Crossing over Yy yy Yy yy yw has occurred for ww Ww Ww ww the YW and yw If the genes were unlinked, then crossing over would not have occurred and the resulting genotypes would have a 1:1:1:1 ratio. In Morgan’s experiment, the genes were linked. Crossing over occurred, and it resulted in 214 flies showing recombinant phenotypes out of the total 21,736 flies. Recombinant Frequency o # of recombinant phenotypes = recombinant frequency Total # of F generation 2 Where are the genes relative to each other on the chromosome? o A big recombinant frequency (rf) means two genes are far away from each other on the chromosome A big rf also means: More recombinant progeny between two genes Bigger range for crossing over to occur and effect the genes More likely to get recombinant progeny o A small rf means two genes are close together on the chromosome Rule for Crossing Over o If it happens, it doesn’t necessarily effect the genes.