Solution :
Red is dominant over the white leaves and pointed is dominant over smooth.
Red = R , white = r
Pointed = P , smooth = p
Red, pointed x white,smooth ------ Parents
RRPP rrpp
RP rp ----------------- Gametes
RrPp -------- ![$F_1$](https://tex.z-dn.net/?f=%24F_1%24)
(red, pointed)
When this
is test crossed,
RrPp x rrpp ----
test cross
Gametes → rp
RP ---------- RrPp - red, pointed - 36 parental type
Rp ---------- Rprp - red, smooth - 14 re- combination
rP ----------- rrPp - white pointed - 10 re- combination
rp ----------- rrpp - white, smooth - 40 - parental type
Total = 100
As this ratio is deviating from 1:1:1:1, it indicated the two genes are linked.
Linkage strength = percentage of crossing over = map distance between the genes.
Percentage crossing = recombination frequency = percentage of recombination.
Recombination frequency ![$=\frac{\text{total no. of recombination}}{\text{total no. of progeny}}\times 100$](https://tex.z-dn.net/?f=%24%3D%5Cfrac%7B%5Ctext%7Btotal%20no.%20of%20recombination%7D%7D%7B%5Ctext%7Btotal%20no.%20of%20progeny%7D%7D%5Ctimes%20100%24)
![$=\frac{14+10}{100} \times 100$](https://tex.z-dn.net/?f=%24%3D%5Cfrac%7B14%2B10%7D%7B100%7D%20%5Ctimes%20100%24)
= 24 %
= 24 map units