Plants of a particular species can either have the dominant wild-type phenotype , tall (T), or the recessive phenotype called dwarf (D). Consider that genetic analysis has identified the stature gene, and DNA analysis of tall plants yields a DNA fragment of 7.5 kb corresponding to a portion of the gene. The wild-type gene map is shown, along with an autoradiograph showing DNA restriction fragments from a normal parental plant (T; lane 1 ), a tall plant that carries a copy of the mutant allele (T; lane 2 ), the two DNA fragment patterns observed in tall progeny plants (T; lanes 3 and 4 ), and the DNA fragment pattern seen in dwarf plants (D; lane 5 ). Using this information, answer the following: Propose two mutational events that could cause the small DNA fragment that represents the mutant allele. In northern blot analysis of mRNA, what mRNA differences would you anticipate for your two proposed mutational mechanisms? Introduction: The wild type dominant gene produces tall plants, and recessive genes are responsible for production of dwarf plants. The wild type gene gives a fragment of length around 7.5 kb. This gene codes for the trait – tall plants. On the other hand, mutant allele gives a fragment of length around 4 kb. It codes for dwarf trait. Organisms that are homozygous for DNA sequence, the same restriction fragments are produced. On the other hand, heterozygous organisms have different DNA sequences and produce different restriction fragments.

Question

Want to see the full answer?

Answer 1

Question

Chapter 10, Problem 24P

Summary Introduction

To analyze:

Plants of a particular species can either have the dominant wild-type phenotype, tall (T), or the recessive phenotype called dwarf (D). Consider that genetic analysis has identified the stature gene, and DNA analysis of tall plants yields a DNA fragment of 7.5 kb corresponding to a portion of the gene. The wild-type gene map is shown, along with an autoradiograph showing DNA restriction fragments from a normal parental plant (T; lane 1), a tall plant that carries a copy of the mutant allele (T; lane 2), the two DNA fragment patterns observed in tall progeny plants (T; lanes 3 and 4), and the DNA fragment pattern seen in dwarf plants (D; lane 5).

Using this information, answer the following:

Propose two mutational events that could cause the small DNA fragment that represents the mutant allele.

In northern blot analysis of mRNA, what mRNA differences would you anticipate for your two proposed mutational mechanisms?

Introduction:

The wild type dominant gene produces tall plants, and recessive genes are responsible for production of dwarf plants. The wild type gene gives a fragment of length around 7.5 kb. This gene codes for the trait – tall plants. On the other hand, mutant allele gives a fragment of length around 4 kb. It codes for dwarf trait. Organisms that are homozygous for DNA sequence, the same restriction fragments are produced. On the other hand, heterozygous organisms have different DNA sequences and produce different restriction fragments.

Expert Solution & Answer

Want to see the full answer?

Check out a sample textbook solution

See solution

Students have asked these similar questions

Consider a maize plant: Genotype C/cm ; Ac/Ac+ where cm is an unstable colorless allele caused by Ds insertion. What phenotypic ratios would be produced and in what proportions when this plant is crossed with a mutant c/c Ac+/Ac+? Assume that the Ac and c loci are unlinked, that the chromosome-breakage frequency is negligible, and the C allele encodes pigment production.

3) You have identified an interesting mutant in gene P. Using a Punnett square, demonstrate the cross you perform to determine if it is a dominant or recessive mutation compared to the WT gene P allele. Write the expected ratios for either scenario. 4) You have determined the mutation is dominant when compared to the WT allele. Briefly describe a technique you could use to determine if expression levels of gene P have been altered in this mutant. 5) You have determined the expression level of gene P has increased. What class/type of mutation would cause this?

When a female melanotic fly is crossed with a normal male, the progeny are produced: 123 normal females, 125 melanotic females, and 124 normal males. In subsequent crosses between melanotic females and normal males, melanotic females are frequently obtained, but never any melanotic males. Provide a possible explanation for the inhertiacne of the melanotic mutation (Hint: The cross produces twice as many female progeny as male progeny)