18The way to show the pos-sible pairings of genesbetween two organisms iscalled a Punnett Square.
19Punnett SquareA Punnett square is used to show the possible combinations of gametes.
20Breed the P generationtall (TT) vs. dwarf (tt) pea plantsTt
21tall (TT) vs. dwarf (tt) pea plants All Tt = tall(heterozygous tall)produces theF1 generationTt
22Breed the F1 generationHeterozygous Tall (Tt) pea plantsT tTt
23Cross a purebred blackguinea pig and apurebred brown guinea pig. Black is dominantover brown.
24B B (black) Bb Bb b Bb Bb b (Brown) All offspringare black and heterozygous.BbBbb(Brown)
25If bushy eyebrows (B) are dominant over fine eyebrows, (b), show the cross between one parent heterozygous for the trait and one who ishomozygous recessive.
26What are the phenotypes and genotypes of theoffspring?Answer: Bushy (Bb) 50%and fine (bb) 50%
27Monohybrid CrossA breeding experiment that tracks the inheritance of a single trait.Dihybrid CrossA breeding experiment that tracksthe inheritance of two traits.
28Mendel’s “principle of segregation” a. pairs of genes on homologous chromosomes separateduring gamete formation (meiosis)and end up in different gametes.b. the fusion of gametes atfertilization pairs genes once again.Ex: The alleles for height in Mendel’spea plants end up in separate gametes. Tt X Tt could yield fourthe offspring: TT, Tt, Tt, tt.
29Meiosis - eye color B B Bb b b sperm haploid (n) diploid (2n) meiosis IIBbmeiosis IBbdiploid (2n)
31Mendel’s “principle of independent assortment” (2 different genes) a. each pair of alleles on nonhomologous chromosomes segregates independently of other pairs during gamete formationEx: When Mendel crossed F1 plants that were heterozygous forround yellow peas, some F2 plantsdid not resemble the parent plants.
32Independent Assortment How many different gametes can be produced for the following allele arrangements?Remember: 2n (n = # of heterozygotes)1. RrYy2. AaBbCCDd3. MmNnOoPPQQRrssTtUu
33Answers: 1. RrYy: 2n = 22 = 4 gametes RY Ry rY ry 2. AaBbCCDd: 2n = 23 = 8 gametesABCD ABCd AbCD AbCdaBCD aBCd abCD abCD3. MmNnOoPPQQRrssTtUu: 2n = 26 = 64 gametes
34Autosomal Inherited Traits are inherited via the autosomes (non-sex)chromosomes. How manyautosomes are in eachof your somatic cells?
35That’s right! There are 44autosomes and 2 sex chro-mosomes in each of yoursomatic (non-sex) cells.
36Figure 13.x5 Human male karyotype shown by bright field G-banding of chromosomes
47If a man who does not have Cystic Fibrosis has a sister who died of CF If a man who does not have Cystic Fibrosis has a sister who died of CF. He marries a woman who does not have the disease or any history of it in her family, what is the probability that they will have kids with the disease?
48Tay Sachs Disease a lipid-digesting enzyme is defective in lysosomes
49If two parents are eachcarriers of the gene forTay-Sachs Disease, whatis the probability of themhaving a child with thedisease?
50That’s right! They have a 25% chance! HomozygousDominantHeterozygousttTttHomozygousRecessive
69If a female who is carrier for Duchenne MuscularDystrophy (D), what is the probability of sheand her“normal”husband having a child with MD?
70D d X X D D d D D X X X X X D d Y X Y X Y Normal Male with Disease Carrier FemaleDdYX YX YMale with Disease
71A pedigree shows the genetic relationship between organisms or people.
72Bloodtypes are alsoinherited:A = has antigen AB = has antigen BO =neitherAB =has both antigensA and B
73A = AA or AO (codominance) GenotypesO = OOAB = ABA = AA or AO (codominance)B = BB or BO(codominance)
74Alleles and Genes Interact to Produce Phenotypes Codominance—two alleles of a gene produce phenotypes that are both present in the heterozygote.Example: ABO blood group system has three alleles of the gene: IA, IB, and IO.See Chapter 31
75ABO Blood Reactions Are Important in Transfusions 75
76O is the universaldonor (can donateblood to anyone)AB is the universalrecipient ( can receive blood from anyone)
77Patient DonorA A or OB B or OAB anyoneO Oa person who is Rh negative for any blood type must take only Rh negative blood
78The Rh Factor is also inherited. Approximately 85% of Americans are positive for the Rh Factor.For example, if you have type A blood and are positive for the Rh Factor then your bloodtype is A positive.
79So technically there are 8 blood groups:A positive AB positiveA negative AB negativeB positive O positiveB negative O negative
80In terms of a couple having kids, positive blood dominates negative blood.For example, a father with A positive blood and his wifewith A negative blood would have kids with A positiveblood.
81RhoGAMA woman who is pregnant and is Rh negative and has an Rh positive child must take RhoGAM in order to not reject the child.
82If a woman who istype O and a manwho is type A havekids, what are their possible bloodtypes?
851) If a brown eyed man marries a brown eyed woman and they have a blue eyed child, what are the genotypes of the parents?
862) In rabbits, the allele for black coat color (B) is dominant over the allelefor brown coat color (b). Predictthe results of a cross between arabbit homozygous for black coatcolor (BB) and a rabbit homozygousfor brown coat color (bb)
873) If two sisters in a family have free earlobes (F) and their two brothershave attached earlobes (f), whatgenotypes are the parents mostlikely to have if neither parent hasattached earlobes?
884) What is the probability of a couple who are both heterozygous for widow’s peak (W) and free earlobes (F) having a child with neither trait?
895) In pea plants, smooth seed texture is dominant over wrinkled seedtexture. A gardener has a peaplant that produces smooth seeds. How can the gardener determinewhether the plant is homozygousor heterozygous for the allele thatdetermines seed texture?
906) In pea plants, if purple flowers are dominant over white, andsmooth seeds are dominantover wrinkled, predict the out-come of the crossing of a peaplant heterozygous for colorand homozygous recessive forseed coat texture with oneheterozygous for both traits.
917) In fruit flies, L = long wings and l = short wings. When along-winged fly is crossed with ashort-winged fly, the offspringexhibit a 1:1 ratio.What is the genotype of theparent flies?
928) In squash an allele for white color (W) is dominant over yellow (w). Give the phenotypic ratios for the results of each of the following crosses:a) W/W x w/wb) W/w x w/wc) W/w x W/w
939) In humans, pointed eyebrows (B) are dominant over smootheyebrows (b). Mary’s father has pointed eyebrows, but she andher mother have smooth. Whatis the genotype of the father?
9410) In tomatoes, red fruit (R) is dominantover yellow fruit (r), andtallness (T) is dominant overshortness (t). A plant that is RrTTis crossed with aplant that is rrTt.What are the chances of an offspringbeingheterozygous for both traits?
9511) In fruit flies, gray wings (G) are dominant to black wings and normalwing length (N) is dominant to vestigial (short) wing length. What is the probability of a gray fly with normalwings heterozygous for both traits and a black fly with normal wings, but homozygous for wing length having offspring which aregray and have normal wing lengths?
9612) Free ear lobes (F) and widow’s peak (W) are dominant traits in humans. What is the probability of a woman who has attached earlobes and no widow’s peak and a man who is heterozygousfor both traits having kids who haveattached ear lobes and no widow’speak?
97Genes A and B are 6 map units apart, and A and C are 4 map units apart Genes A and B are 6 map units apart, and A and C are 4 map units apart. Which gene is in the middle if B and C are 10 map units apart? Which is in the middle if B and C are 2 map units apart?
98In the cross RrTt X rrtt,all of the offspring will be tall with red fruitb. 75% will be tall with red fruitc. 50% will be tall with red fruitd. 25% will be tall with red fruit
99In terms of evolution, why is the incidence of sicklecell anemia higher among theAfrican-American populationin the United States?
100If one parent has type O blood and one of the kids is type A,what are the possible blood types of the other parent?If one parent has type AB blood and the other has A, what are the possible blood types of the kids?
101For most human traits, how many alleles does each parent contribute to the zygote or fertilized egg? What is the term used to describe traits that are inheritedby a number of genes of eachparent?
102show a Punnett square with the inheritance pattern If you have good notes from yesterdayon Cystic Fibrosis you should be able to:describe at least two organs affectedshow a Punnett square with theinheritance pattern3) list one organization which raisesawareness of CF4) name and describe the specific protein affected by CF5) significance of discovery of the CF gene
103When RhoGAM is given to a pregnant mother,what is the Rh status of themother, father, and baby?