Exam 15: The Dynamic Genome: Transposable Elements

The first eukaryotic transposable elements to be characterized at the molecular level were identified within the genes of which organism?

In D.melanogaster,when P cytotype (lab stock)females are crossed to M cytotype (wild)males,the resulting F₁ progeny are:

Which of the following scientists discovered the Ac-Ds transposable elements in maize?

IS-induced mutations are different from missense mutations in that they are:

Hybridization of single-stranded wild-type DNA with DNA from mutations caused by IS elements characteristically shows (through electron microscopy):

Transposable elements that are comprised of DNA transposons are known as:

The grasses (such as barley,rice,sorghum,and corn)vary widely in the size of their genomes,yet they are descended from a common ancestor.What accounts for the variation in DNA content (i.e.,the total amount of DNA)?

A maize plant is homozygous for an allele C^m,caused by the insertion of a Ds element into the coding region of a gene (C)that encodes an enzyme necessary for the synthesis of anthocyanin in maize kernels. a)If this plant also contains an Ac element in its genome,what will be the phenotype of its kernels? Justify your answers. b)If this plant does not contain an Ac element,what will be the kernel phenotype? Justify your answers. c)If the plant does not contain an Ac element,but it does contain an autonomous element for another family of transposon,what will be the kernel phenotype? Justify your answers.

Transposable elements can cause corn kernels to be spotted if they jump in or out of the color genes during the development of the kernel.However,the size of the spots can vary greatly.In words and diagrams,describe the difference between the two kernels shown below at the molecular and developmental levels.

In D.melanogaster,when M cytotype (lab stock)females are crossed to P cytotype (wild)males,the resulting F₁ progeny are:

The movement of transposable elements can cause either forward mutations or reversions. a)Define "forward mutations" and "reversions," and describe the transposition events that cause these two types of phenotypic changes. b)Why did Barbara McClintock focus on reversions rather than forward mutations when she first studied the inheritance of transposable elements in maize?

Transposable elements that transpose via an RNA intermediate is known as:

Compare and contrast autonomous and nonautonomous transposable elements.

Bacterial transposon structure can be thought of as:

a)What is the C-value paradox? b)What is the explanation for the C-value paradox?

Which of the following statements is/are TRUE about the P elements of Drosophila?

A corn plant is homozygous for a mutant allele that results in no pigment in the seed (i.e.,white).The mutant is caused by Ds insertion that often exits late in seed development,when there is an active Ac element in the genome.The seeds of this plant will be:

Approximately 45 percent of the human genome is derived from transposable elements,such as LINEs and SINEs. a)What are LINEs and SINEs? b)How do LINEs differ from SINEs? c)How is survival possible with this high a percentage of transposable elements in the human genome?

LINEs differ from retrotransposons in that LINEs do not: