Q. How many types of gametes may be produced by genotype D/d: E/e: F/f?
Rajasthan PMTRajasthan PMT 2001
Solution:
Kinds of gametes may be calculated by following formula:
Number of gametes $=(2)^{n}$ n is number of alleles
Example: D/d: E/e: F/f have trihybrid cross, i.e. n = 3 than
Kind of gametes $=(2)^{3}=2 \times 2 \times 2=8$
No. of alleles (n)
type of cross
Formula
Kinds of gametes
1
Monohybrid cross
$(2)^{1} = 2\times 1$
$2$
2
Dihybrid cross
$(2)^{2} = 2\times 2$
$4$
3
Trihybrid cross
$(2)^{3} = 2\times 2 \times 2$
$8$
4
Polyhybrid cross
$(2)^{4} = 2\times 2 \times 2\times 2\times$
$16$
5
Polyhybrid cross
$(2)^{5} = 2\times 2\times 2\times 2\times 2$
$32$
| No. of alleles (n) | type of cross | Formula | Kinds of gametes |
|---|---|---|---|
| 1 | Monohybrid cross | $(2)^{1} = 2\times 1$ | $2$ |
| 2 | Dihybrid cross | $(2)^{2} = 2\times 2$ | $4$ |
| 3 | Trihybrid cross | $(2)^{3} = 2\times 2 \times 2$ | $8$ |
| 4 | Polyhybrid cross | $(2)^{4} = 2\times 2 \times 2\times 2\times$ | $16$ |
| 5 | Polyhybrid cross | $(2)^{5} = 2\times 2\times 2\times 2\times 2$ | $32$ |