p1 p2 p3 r1 r2 r3 r4 p1 - + + + - + + p2 - + - + + - p3 - + + - + r1 - + + - r2
ID: 188923 • Letter: P
Question
p1
p2
p3
r1
r2
r3
r4
p1
-
+
+
+
-
+
+
p2
-
+
-
+
+
-
p3
-
+
+
-
+
r1
-
+
+
-
r2
-
+
+
r3
-
+
r4
-
A lab in Seattle is interested in understanding the genetics of flower petal development in petunias. After doing mutagenesis on the plant and screening the mutant products, they identify three homozygous recessive mutant strains that all fail to form petals; they call these mutants strains p1 through p3. Meanwhile, they hear from their friends in Mankato, Minnesota, who had done a similar screen and identified four recessive mutant alleles r1 through r4 that also failed to form flower petals. The labs exchange strains and perform crosses between the various strains; the ability (+) or inability (-) of the progeny to form petals is indicated:
How many genes are represented in this collection of mutant strains?
Which mutants represent alleles of the same gene?
p1
p2
p3
r1
r2
r3
r4
p1
-
+
+
+
-
+
+
p2
-
+
-
+
+
-
p3
-
+
+
-
+
r1
-
+
+
-
r2
-
+
+
r3
-
+
r4
-
Explanation / Answer
Ans.According to the table above there are two types of genes which are dominant and recessive.
The mutants which are crossed with themselves show alleles of same genes.Because by looking at the punett square the crosses p1*p1, p2*p2, p3*p3, r1*r1, r2*r2, r3*r3, r4*r4 are homozygous recessive for plants showing inability to form petals. Other genes are probably heterozygous showing ability to form petals
Related Questions
Navigate
Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.