Researchers cross a corn plant that is purebreeding for the

Researchers cross a corn plant that is pure-breeding for the dominant traits colored aleurone (C1), full kernel (Sh), and waxy endosperm (Wx) to a pure-breeding plant with the recessive traits colorless aleurone (c1), shrunken kernel (sh), and starchy (wx).

Part F

Problem 5.13 Kernel Phenotype Number Colored, shrunken, starchy 116 601 Colored, full, starchy Colored, full, waxy 2538 Colored, shrunken, waxy Colorless, shrunken starchy 2708 2 Colorless, full, starchy Colorless, full, waxy 113 Colorless, shrunken, waxy 626 6708 Submit My Answers Give Up Correct Part E Calculate the recombination fraction between the C-Wx gene pair Enter your answer to three decimal places (example 0.234) Recombination fraction .219 Submit My Answers Give Up Correct Part F What is the interference value for this data set? Enter your answer to three decimal places (example 0.234) Interference value Submit My Answers Give Up

Solution

Answer:

Part E); 0.217

Part F). 0.333

Shorthand

Number of progeny

C1sh wx

116

C1 Sh wx

601

C1 Sh Wx

2538

C1 sh Wx

4

c1 sh wx

2708

c1 Sh wx

2

c1 Sh Wx

113

c1 sh Wx

626

Imagine parental combinantion = C1 Sh Wx & c1 sh wx

1.    If single cross over (SCO) occurs between C1 & Sh

Normal order= C1---------Sh & c1-----sh

After cross over= C1-----sh & c1------Sh

C1-----sh recombinants are 116+4=120

c1------Sh recombinants are 113+2=115

Total recombinants = 335

RF = (335/6708)*100 =0.05%

2.    If single cross over (SCO) occurs between Sh & Wx

Normal order= Sh---------Wx & sh----wx

After cross over= Sh-----wx & sh------Wx

Sh-----wx recombinants are 601+2=603

sh------Wx recombinants are 626+4=630

Total recombinants = 1233

RF = (1233/6708)*100 = 18.38%

3.    If single cross over (SCO) occurs between C1 & Wx

Normal order= C1---------Wx & c1------wx

After cross over= C1-----wx & c1------Wx

C1-----wx recombinants are 116+601=717

c1------Wx recombinants are 113+626=739

Total recombinants = 1456

RF = (1456/6708)*100 =21.7%

% RF = Map unit distance

The order of genes is -----

C1------5 m.u.--Sh-------18.38m.u.---------Wx

RF between C1&Sh= 0.05

RF between v & s = 0.18%

Expected double cross overs = 0.05 * 0.18 = 0.009

Observed double cross overs = 4% + 2%

= 6= 0.006

Observed double cross progeny are more than the expected double cross over progeny.

Coefficent of coincidence (CC) = Obeserved dco / Expected dco

CC = 0.006/0.009 = 0.66

Interference = 1-CC = 1-0.66 = 0.34

Shorthand	Number of progeny
C1sh wx	116
C1 Sh wx	601
C1 Sh Wx	2538
C1 sh Wx	4
c1 sh wx	2708
c1 Sh wx	2
c1 Sh Wx	113
c1 sh Wx	626