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(1 point) In a species of snapdragons, flowers can be white, solid yellow, or sp

ID: 79246 • Letter: #

Question

(1 point) In a species of snapdragons, flowers can be white, solid yellow, or spotted. This trait is determined by two separate gene loci. The first gene locus determines pigmentation pattern, where solid yellow (Y) is dominant over spotted (y). The second gene locus produces an inhibitor of pigment production, where the dominant I results in inhibition of pigment production (and therefore white color) and the recessive i does not result in inhibition of pigment production (so that the solid yellow or spotted phenotypes are visible) a) What class of epistasis (recessive, dominant, or complementary gene action) is represented by this example? Explain your answer. b) Based on the description above, determine the phenotype of each of the following genotypic classes: Y I Y ii yy yyii: c For each of the following crosses, determine the genotypes of both parents Phenotypes of offspring Phenotypes of Parents 1) White X Solid Yellow 100 white, 80 Solid Yellow; 28 Spotted 2) White X Solid Yellow 102 white, 48 Solid Yellow, 52 Spotted 3) White X Spotted 105 white; 45 Solid Yellow; 48 Spotted 4) Solid Yellow X Solid Yellow 148 Solid Yellow; 55 Spotted 5) White X White 145 white; 43 Spotted 200 white 60 White X Solid Yellow

Explanation / Answer

Answer:

a). Dominant epistasis

b).

Y_I_ : White

Y_ii : Solid yellow

yyI_ : white

yyii : spotted

c).

Parents

Offsprings

Cross no

Phenotype

Gneotype

Phenotype

Gneotype

Phenotypes

1

White

YyIi

Solid yellow

Yyii

100 white

80 solid yellow

28 spotted

2

White

yyIi

Solid yellow

Yyii

102 white

48 solid yellow

52 spotted

3

White

YyIi

Spotted

yyii

105 white

45 solid yellow

48 spotted

4

Solid yellow

Yyii

Solid yellow

Yyii

148 solid yellow

55 Spotted

5

White

yyIi

White

yyIi

145 white

43spotted

6

White

YYII

Solid yellow

YYii

200 white

d)

White of cross 1 (YyIi) X Solid yellow of cross 2 (YYii)------Parents

Yi

YI

YYIi (white)

Yi

YYii (Solid yellow)

yI

YyIi (White)

yi

Yyii (Solid yellow)

White : Solid yellow = 1 : 1

Parents

Offsprings

Cross no

Phenotype

Gneotype

Phenotype

Gneotype

Phenotypes

1

White

YyIi

Solid yellow

Yyii

100 white

80 solid yellow

28 spotted

2

White

yyIi

Solid yellow

Yyii

102 white

48 solid yellow

52 spotted

3

White

YyIi

Spotted

yyii

105 white

45 solid yellow

48 spotted

4

Solid yellow

Yyii

Solid yellow

Yyii

148 solid yellow

55 Spotted

5

White

yyIi

White

yyIi

145 white

43spotted

6

White

YYII

Solid yellow

YYii

200 white