Complete question:
You will find the complete question in the attached files
Answer:
- For the twist trait: The <em>mutant allele is dominant</em> to its corresponding wild-type allele
- For the forked trait: the <em>mutant allele is dominant</em> to its corresponding wild-type allele
- For the pale trait: The <em>mutant allele is neither dominant nor completely recessive</em> to its corresponding wild-type allele
Explanation:
- Cross 1: twisted x wild-type ----> Pure lines
Parentals) TT x tt
<em>F1) twisted leaves, Tt</em>. ---> Heterozygous
Parentals) Tt x Tt
Punnett square) T t
T TT Tt
t Tt tt
<em>F2) 53 twisted, 18 wild-type </em>
Total number of individuals in the F2 = 53 + 18 = 71
71 plants -------- 100% of the F2
53 twisted------X = 75% TT + Tt
18 wild-type----X = 25% tt
<em>Phenotypic ratio 3:1</em>
The phenotype of the F1 and F2 progeny tells us that the twist trait is dominant over the wild type. The fact that the whole F1 generation was twisted is enough information to assume that the wild type is recessive and the twisted is dominant. Also, the phenotypic ratio of the F2 corroborates this assumption.
- Cross 2: forked x wild-type ---> Pure Lines
Parentals) FF x ff
F1) 100% forked, Ff----> Heterozygous
Parentals) Ff x Ff
Punnett square) F f
F FF Ff
f Ff ff
F2) 49 forked and 16 wild-type plants
Total number of individuals in the F2 = 49 + 16 = 65
65 plants -------- 100% of the F2
49 forked------X = 75% FF + Ff
16 wild-type----X = 25% ff
<em>Phenotypic ratio 3:1</em>
The phenotype of the F1 and F2 progeny tells us that the twist trait is dominant over the wild type. The fact that the whole F1 generation was forked is enough information to assume that the wild type is recessive and the forked is dominant. Also, the phenotypic ratio of the F2 corroborates this assumption.
- Cross 3: pale x wild-type ---> Pure lines
Parentals) PP x pp
F1) 100% Pp, intermediate color.
Parentals) Pp x Pp
Punnett square) P p
P PP Pp
p Pp pp
F2) 34 intermediate, 17 wild-types, and 16 pale.
Total number of individuals in the F2 = 34 + 17 + 16 = 67
67 plants -------------- 100% of the F2
34 intermediate ------X = 51% Pp
17 wild-type-------------X = 25% pp
16 pale -------------------X = 24% PP
<em>Phenotypic ratio 1:2:1</em>
The phenotype of the F1 and F2 progeny tells us that the pale trait is not dominant neither recessive to the wild type. The fact that the whole F1 generation was intermediate is enough information to assume that none of the traits dominates over the other. This is a case of incomplete dominance. The heterozygous individual express an intermediate phenotype between both the parentals´ one. Also, the phenotypic ratio of the F2 corroborates this assumption.
