NAME_____________________________________________&&1&Homework 2 Biol 283, General Genetics Fall, 2014 1. (5 points) Mendel crossed pea plants producing round seeds with those producing wrinkled seeds. From a total of 7,324 F2 seeds, 5,464 were round and 1,860 were wrinkled. Using the symbols R and r for the alleles: a. Using symbols, write the original P1 cross and the F1 cross that is used to produce an F2 b. Write the genotype(s) of the F1 progeny using symbols c. Write the gametes produced by the F1 generation using symbols d. Summarize the expected F2 phenotypes and their frequencies e. Summarize the expected F2 genotypes and their frequenciesNAME_____________________________________________&&2&2. (4 points) How many genetically different gametes could be formed by an individual with the following genotypes? Show your work for partial credit. a. Ff gg hh Ii b. Ff Gg Hh Ii 3. (6 points) In the cross Ff gg hh Ii X Ff Gg Hh Ii what is the probability of obtaining the following offspring: (Show your work for partial credit) a. phenotypically FGHI (all dominant) b. genotypically ff gg hh ii c. genotypically Ff gg hh IINAME_____________________________________________&&3&4. (5 points) In Drosphilia melanogaster (fruit flies), the gene ey causes the fly to be eyeless, and is recessive to the wild type (WT) allele, ey+. The b gene, which is recessive to the WT allele b+, causes the flies to have black bodies. WT fruit flies are brown. For the following crosses, calculate the probability that an offspring will be phenotypically identical to one of its parents. Please be clear: state the phenotypes of the parents and show your calculations. a. (1 point) ey/ey b+/b+ X ey+/ey+ b/b b. (2 points) ey/ey+ b/b+ X ey/ey+ b/b+ c. (2 points) ey/ey+ b/b+ X ey/ey+ b/bNAME_____________________________________________&&4& Pedigree&for&questions&5&6:&&&5.&&(5&points)&If&the&trait&in&the&pedigree&is&autosomal&DOMINANT&a. State&which&(if&any)&individual(s)&in&the&pedigree&have&UNKNOWN&genotypes.&&&&b. State&which&(if&any)&individual(s)&in&the&pedigree&are&HOMOZYGOUS&&&&&&c. State&which&(if&any)&individual(s)&in&the&pedigree&are&HETEROZYGOUS&&&&&&d. what&is&the&probability&that&future&children&of&II.3&and&II.4&will&be&affected?&&&&&&e. what&is&the&probability&that&future&children&of&II.7&and&II.8&will&be&affected?&&&NAME_____________________________________________&&5&6.&(5&points)&&If&the&trait&in&the&pedigree&above&is&autosomal&RECESSIVE&a. State&which&(if&any)&individual(s)&in&the&pedigree&have&UNKNOWN&genotypes.&&&&b. State&which&(if&any)&individual(s)&in&the&pedigree&are&HOMOZYGOUS&&&&&&c. State&which&(if&any)&individual(s)&in&the&pedigree&are&HETEROZYGOUS&&&&&&d. what&is&the&probability&that&future&children&of&II.7&and&II.8&will&be&affected?&&&&&&e. Calculate&the&probability&that&III.9&is&a&carrier&&&&&&7.& (5 points) Using the data in the following table, determine which parent(s) must be homozygous. Cross Parents Progeny Female X Male spotted solid A spotted X solid 102 98 B spotted X spotted 160 53 C solid X solid 0 183 D spotted X solid 174 0 E spotted X spotted 210 0 Female A must be homozygous YES NO Female B must be homozygous YES NO Female C must be homozygous YES NO Female D must be homozygous YES NO Female E must be homozygous YES NONAME_____________________________________________&&6&8.&&(5&points)&The&following&is&the&pedigree&for&a&family&exhibiting&a&RARE&autosomal&recessive&disorder&called&Friedreich&ataxia.&&The&Nationa l &Institute&of&Neurological&Disorders&and&Stroke&describes&Friedreich&ataxia,&“Friedreich's&(sic)&ataxia&(al so&called&FA&or&FRDA)&is&a&rare&inherited&disease&that&causes&nervous&system&damage&and&movement&problems.&It&usually&begins&in&childhood&and&leads&to&impaired&muscle&coordination&(ataxia)&that&worsens&over&time…&Although&rare,&Friedreich’s&(sic)&ataxia&is&the&most&common&form&of&hereditary&ataxia,&affecting&about&1&in&every&50,000&people&in&the&United&States.”&&&Since&Friedreich&ataxia&is&very&rare,&you&may&assume&that,&unless&a&specific&probability&can&be&calculated&based&on&a&person’s&genetic&history,&the&chance&of&their&being&a&carrier&is&zero.&&&&a. What&is&the&probability&that&II.3&is&a&carrier&for&Friedreich&ataxia?&&&&&&&b. What&is&the&probability&that&III.2&is&a&carrier&for&Friedreich&ataxia?&&&&&&&&c. What&is&the&probability&that&II.5&is&a&carrier&for&Friedreich&ataxia?&&&NAME_____________________________________________&&7&&&d. What&is&the&probability&that&III.3&is&a&carrier&for&Friedreich&ataxia?&&&&&&&e. What&is&the&probability&that&IV.1&(the&unborn&child&of&III.2&and&III.3)&will&have&Friedreich&ataxia?&&&&&&&&&NAME_____________________________________________&&8&9. (5 points) “Marfan&syndrome&…&is&a&genetic&disorder&of&human&connective&tissue.&It&has&various&expressions&ranging&from&mild&to&severe:&the&most&serious&complications&are&defects&of&the&heart&valves&and&aorta,&which&often&lead&to&early&death…&People&with&Marfan&tend&to&be&unusually&tall,&with&long&limbs&and&long,&thin&fingers. &The&syndrome&is&caused&by&the&misfolding&of&the&protein&fibrillinf1.&Fibrillinf1&is&coded&by&the&gene&FBN1.&Fibrillinf1&protein&forms&fibers&in&connective&tissue.”&from&the&Wikipedia&Article&on&Marfan&Syndrome&&Marfan&syndrome&is&dominant.&&The&most&common&Marfanfcausing&allele&is&called&C1663R.&&An&important&experiment&to&distinguish&the&mechanism&of&this&dominance&was&performed&using&a&mouse&model&system.&&The&researchers&introduced&the&human&C1663R&allele&into&mice,&and&demonstrated&that&the&protein&encoded&by&C1663R&was&being&expressed&correctly&(right&time,&right&place,&right&amount).&&Note&that&these&mice&also&have&their&own,&normal&FBN1&genes&that&continue&to&function.&&a. What&phenotype&is&expected&in&the&mice&carrying&the&human&C1663R&allele&if&Marfan&syndrome&is&the&result&of&a&dominant&negative&allele?&&You&may&explain&your&answer&in&3&sentences&or&less.&&&&&&&&&&&b. What&phenotype&is&expected&in&the&mice&carrying&the&human&C1663R&allele&if&Marfan&syndrome&is&the&result&of&haploinsufficency?&?&&You&may&explain&your&answer&in&3&sentences&or&less.&&&&&&&&