Two linked plus one unlinked gene pattern Phenotype Numbers

Two linked plus one unlinked gene pattern Phenotype Numbers 301 Parental CV VAC 273 Parental ICH v 80 Recombinant .le cl\'s unlini t v cl 297 Parental it means chroni 90 Recombinant some v cv cl v 86 Recombinant but tn genie CV v 84 Recombinant V cum CV V 289 Parental Wet Total 1500

Solution

Answer:

Explanation

Shorthand

Number of progeny

CV V cl

301

+ + cl

273

+ V cl

80

+ + +

297

CV + cl

90

CV + +

86

+ V +

84

CV V +

289

Imagine the order is CV V cl/+ + +

1.    If single cross over (SCO) occurs between CV & V

Normal order= CV---------V & +-----+

After cross over= CV-----+ & +------V

CV-----+ recombinants are 90+ 86 = 176

+------V recombinants are 80+ 84 = 164

Total recombinants = 340

RF = (340/1500.)*100 =22.7%

2.    If single cross over (SCO) occurs between V & cl

Normal order= V---------cl & +----+

After cross over= V-----+ & +------cl

V-----+ recombinants are 84+289 = 373

+------cl recombinants are 90+273 = 363

Total recombinants = 736

RF = (736/1500)*100 = 49.06%

3.    If single cross over (SCO) occurs between CV & cl

Normal order= CV---------cl & +------+

After cross over= CV-----+ & +------c;

CV-----+ recombinants are 86+289 = 375

+------cl recombinants are 80+ 273 = 353

Total recombinants = 728

RF = (728/11500)*100 = 48.53%

% RF = Map unit distance

The order of genes is -----

V------22.7 m.u.--------CV------48.53 m.u..-------cl

The gene V & CV are linked and the gene cl is unlinked

Shorthand	Number of progeny
CV V cl	301
+ + cl	273
+ V cl	80
+ + +	297
CV + cl	90
CV + +	86
+ V +	84
CV V +	289