7 Compulsive channel switching ie channel surfing is found t

7. Compulsive channel switching (i.e. channel surfing) is found to be caused by a recessive (but highly prevalent) gene on the X chromosome (cs). Also located on the X chromosome are two other recessive genes - one that causes an addiction to watching football on TV (fba), and one that causes excessive burping in public (bp). The location of these genes on the X chromosome are 25 (cs/ cs+), 43 (fba/fba+) and 76 (bp/bp+) map units. The level of interference over this linkage group (i.e. the Coefficient of Interference) is 0.15. A normal female has the genotype cs+ fba bp+ / cs fba+ bp. What is the probability that she will produce a gamete that contains all three recessive alleles? The answer I calculated is 0.05; is that the probability that she will produce a gamete that contains all three recessive alleles?

Solution

Coefficient of coincidence = (observed DCO) / (expected DCO)

0.15 = 0.25 x 0.43 x 0.76 / expected DCO

Expected Double Cross Over = 0.54