Question

In the Pissum sativum pea plant, round, yellow and gray seed coat are dominant traits, whereas wrinkled (ww), yellow (yy) and white seed coat (gg) are recessive traits. Two plants are crossed to produce 639 offspring with the following phenotypes: round yellow gray 269 round yellow white 98 round green gray 86 wrinkled yellow gray 88 round green white 27 wrinkled yellow white 34 wrinkled green gray 30 wrinkled green white 7 a) What is the genotype of the parents? b) What is the chi-square value? c) How many degrees of freedom? d) The p value lies between:

Answer 1

Round Yellow and Gray = RrYyGg

Wrinkled Green and White = rryygg

Parents ------------------> RrYyGg x rryygg

Gametes ----------------> RYG rYG RYg ryg RyG Ryg rYg ryG ryg

	RYG	rYG	RYg	ryg	RyG	Ryg	rYg	ryG
ryg	RrYyGg Round Yellow gray	rrYyGg Wrinkled Yellow Gray	RrYygg Round Yellow White	rryygg wrinkled green white	RryyGg Roung green Gray	Rryygg Round green White	rrYygg Wrinkled Yellow White	rryyGG Wrinkled green Gray
Observed Frequency (O)	269	88	98	7	86	27	34	30
Expected Frequency (E)	80	80	80	80	80	80	80	80
O-E	189	8	18	-73	6	-53	-46	-50
(O - E)2	35721	64	324	5329	36	2809	2116	2500
(O - E)2/E	446.51	0.8	4.05	66.61	0.45	35.11	26.45	31.25

Chi-square value = 611.23

Degrees of freedom = 8- 1 = 7

At 0.05 probability, T value is 14.07