Name: U"4 Period:

PRACflCE PROBLEMS IN MEHDELIAN GENETICS

Problems lnvolving One Gene1. Mr. and Mrs. Jones have six children. Three of them have attached earlobes (recessive) like their father, and the other

three have free earlobes like their mother. What are the genotypes of Mr. and Mrs. Jones and of their numerousoffspring? $ b Wd€ 'hg.fire (ee-) +h€v e^o\^ ha-d 1o qet o&a- r€L€ss\Me. afk-tq*ttorn e^th ?ar€d-"" Mou's e^vt dvu*ree,dAl'av-e,"rJ-.

$op1= p<- Da-d = {z * !q-As: g;-,e-(Sree) +€-e(att-ar<-\n*A)2. Mr. and Mrs. Anderson hoth have tightly curled hair. {The hair form gene shows incomplete dominance. There are two

alleles, curly and straight. The heterozygote has wavy hair.) The Andersons have a child with wavy hair. Mr. Andersonaccuses Mrs. Anderson of being unfaithfulto him. ls he necessarily justified? Why or why not?

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Problems lnvolving Two Genes3. A man with dark {dominant), curly {see problem 5) hair marries a woman with light, straight hair. Their daughter, who

happens to have dark hair, marries a man with light, wavy hair. Answer the following questions about this dark-haireddaughter and her family.

l. Draw a Punnett's square for this marriage, predict ratio among the offspring of the

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daughter and her husban{.dc lVruruhapiu rahu:

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dsdo,u6h\tr- DdCS eEv ll. What is the chance that they

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t/fV = t/"t or 7rr'1,When a male pig from a line of true-breeding {homozygous) black, solid-hooved pigs was crossed to a female from a

breed (homozygous) of red, cloven-hooved pigs, their several progeny all looked alike with regard to color and hooves.These progeny were all rnated to members of the same breed as their red, cloven-hooved mother pig. The offspringfrom this final cross were: 11 btack, cloven-hooved; 8 black, solid-hooved; 14 red, cloven-hooved; and 10 red, solid-hooved. For each of these two genes (coat color and hoof type) determine which allele is the dominant ene. Explainyour reasoning. What were the phenotypes of the progeny produced by the first mating in thi

-fzEtcrGs+ Bbgsxffi3 "P ,- &v6sxAt\ e<. tss, bSe6@r@tyis{aln garden peas, long stems are dominant to shdrt itbms, and yellow seeds are dominant tolong/yellow pea plants, allof which had one short/green parent, are interbred (bred to each other)" 16@ progenyresult. Please answer the following questions about these progeny.

l. Assuming that these two genes are unlinked, about how many longlgreen pea plants would yo-u expect to find

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What ratio of yellow to green seed color would you expect among the offspring?

12,{ = 3't1ll. What would you expect the overall phenotypic ratio among the 1600 offspring to be (taking into consideration

bothtraits)? Qr 3,'3: \ (tu,,gl,6etl",..r'shsr+1,#..LA;)4, tn'gl6..er.,s\rur't,$**^)

amons the offsprins? tL\ q X Lf"Jg (Z halerBzdsous p4r€,S=- fi. 2 1r^rjB){ 6l"qg7*ot*), 3(shor+/n.lt"d , 3(Iovqi,qvreen)'[ (dnor{ lAr.,

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Problems lnvolving Sex Unkage6. Marian's father is colorblind, as is her maternal grandfather (her mothels father). Marian herself has normal color

vision. Marian and her husband, Martin, who is also colorblind, have just had their first child, a son they have namedMickey. Please answer the following questions about this smallfamily.

l. What is the probability that this child will be colorblind? I I^l/-ll. Three sources of the colorblindness allele are mentioned in this family. lf Mickey is colorblind, from which of

these three men (Marian's grandfather, Marian's father, or Martin) did he inherit the allele?

lttlnnan'( &+hr,,Rlll. Using proper pedigree format diagram the available information about the four generations of this family

described, assuming that Mickey is colorblind.

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7. ln cats, there is a coat color gene located on the X chromosom€. This gene is a different gene from the black/Siamesegene discussed in earlier problems. This gene has two alleles-orange and black. A heterozygous cat has tortoiseshellcolor (a splotchy mixture of orange and black). Predid the genotypic ond phenatypic ratios among the offspring of thefollowing crosses. Pay careful attention to the genders of the offspring.

tauiwlV. lf Martin were not colorblind, how would this affect the prediction about Mickey?

l. BIack female X Orange male

i. Genotyp'."?",f,i(l'1" l*V) phenotypicratio:

ll. Orange female X Black male

i. Genotyp,. 'r,., ii (}.*XttX'l) . phenotypiratio:

lll. Tortoiseshellfemale X Black male

i. Genotypl. .,'r;"' i'i' i-'iiiuXo,J.olV. Tortoiseshellfemale X Orange male

i. Genotypic ratio: l.Ll' I (Xo

Problems tnvolving Genes with Multiple Alleles (nO) (90)8. lna particular family, one parent has Type A blood, the other has Type B. They have four children. One has Type A, one

has Type B, one has Type AB, and the last has Type O. What are the genotypes of all six people in this family?

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Parer*t* \A'L + lo'1 tr "f"d,{t'xl,rt0tr11rrS u,{rvr chit'dr{n.9, ln a recent case in Spokane, \rVashington, a young woman accused a soldier of being the father of her child, The soldier,

of course, denied it. The soldier's lawyer demanded that blood types be taken to prove the innocence of his client. Thei following results were obtained: Alleged father, Type O. Mother, Type A. Child, Type AB. The court found the soldier

guilty on the basis of the woman's remarkable memory for dates and details that apparently eliminated all otherpossibte fathers. Fa*h.ar-il M0++L0r- lA-

l. What are the possible genotypes for these three people? e h\ t d lA \ b

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l-0. A woman has a daughter. There are three mEn whom she clal*rs might have been the father of the child. The judge inthe paternity court orders that allthree men, the child, and the mother have blood tests. The results are: mother, TypeA; Daughter, Type O; Man #1, Type AB; Man #2, Type B; Man #3, Type O. The mother claims that this proves that Man#3mustbethelittlegirl'sfather. mul*u.r- !1to Dauqntgr-ii $an+t-l- iAl_6

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