A transposable element is found to encode a reverse...

Name: Problem 41, Chapter 18: Genetics: A Conceptual Approach
Uploaded: 2020-07-06T20:58:35-08:00
Duration: 57 s
Channel: Carlene Jimenez
Description: A transposable element is found to encode a reverse transcriptase enzyme. On the basis of this information, what conclusions can you draw about the likely structure and method of transposition of this element?

A transposable element is found to encode a reverse transcriptase enzyme. On the basis of this information, what conclusions can you draw about the likely structure and method of transposition of this element?

Key Concepts

Transposable Elements

Transposable elements are mobile segments of DNA capable of moving within a genome. They are categorized into classes based on their method of transposition, with some moving directly as DNA (DNA transposons) and others transposing via an RNA intermediate (retrotransposons).

Reverse Transcriptase

Reverse transcriptase is an enzyme that synthesizes DNA from an RNA template. Its presence in a transposable element indicates that the element likely replicates through an RNA intermediate, a hallmark of retrotransposons rather than DNA transposons.

Retrotransposons

Retrotransposons are a type of transposable element that use an RNA intermediate in their replication cycle. They undergo transcription into RNA, which is then reverse transcribed into DNA by reverse transcriptase and integrated into a new genomic location.

Copy and Paste Mechanism

The method of transposition associated with elements that encode reverse transcriptase is typically characterized as a 'copy and paste' mechanism. This process involves copying the element via an RNA intermediate and reinserting the new copy elsewhere in the genome, leading to an increase in the element's copy number.

Structural Characteristics of Retrotransposons

Retrotransposons often have distinct structural features that facilitate their replication and integration. Many of them are flanked by long terminal repeats (LTRs), which contain regulatory sequences needed for transcription, although some non-LTR retrotransposons exist. These structural elements are integral to their lifecycle and mobility within the genome.

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