Related Experiment Video
Updated: Jun 6, 2026
08:19
Quantitative Comparison of cis-Regulatory Element (CRE) Activities in Transgenic Drosophila melanogaster
Published on: December 19, 2011
Comparative analysis of transposable elements in the melanogaster subgroup sequenced genomes
Emmanuelle Lerat1, Nelly Burlet, Christian Biémont
1Université de Lyon, Lyon, France. emmanuelle.lerat@univ-lyon1.fr
Gene
|December 16, 2010
Summary
Transposable elements (TEs) show different dynamics across closely related Drosophila species. While D. simulans, D. sechellia, and D. yakuba have ancient, degraded TE insertions, D. melanogaster exhibits recent, active TE proliferation, possibly from horizontal transfers.
Area of Science:
- Genomics
- Evolutionary Biology
- Molecular Biology
Background:
- Transposable elements (TEs) are crucial drivers of genome evolution.
- Comparative genomic studies of TEs in closely related species are limited.
- The genomes of Drosophila melanogaster, D. simulans, D. sechellia, and D. yakuba offer a unique system for such comparisons.
Purpose of the Study:
- To analyze and compare the number and structure of transposable element (TE) copies across four closely related Drosophila species.
- To understand the evolutionary dynamics and life cycle stages of TEs in these species.
- To investigate potential horizontal transfer events of TEs between species.
Main Methods:
- Whole-genome sequencing data analysis.
- Identification and quantification of transposable element insertions.
- Comparative sequence analysis of TE copies.
- Phylogenetic analysis to infer transfer events.
Main Results:
- D. simulans has more TE insertions than D. melanogaster, but they are mostly degraded fragments.
- D. melanogaster shows a recent burst of highly similar TE copies, suggesting recent activation.
- TE variants in D. simulans and D. sechellia resemble active D. melanogaster TEs, indicating recent horizontal transfer into D. melanogaster.
Conclusions:
- D. simulans, D. sechellia, and D. yakuba appear to be in a later stage of TE regulation compared to D. melanogaster.
- D. melanogaster has likely experienced recent invasions of active TE variants, possibly from D. simulans or its ancestors.
- Observed TE dynamics suggest significant horizontal transfer and potential introgression events among these Drosophila species.
Related Concept Videos
02:13Overview of Transposition and Recombination
Transposons make up a significant part of genomes of various organisms. Therefore, it is believed that transposition played a major evolutionary role in speciation by changing genome sizes and modifying gene expression patterns. For example, in bacteria, transposition can lead to conferring antibiotic resistance. Movement of transposable elements within the genetic pool of pathogenic bacteria can aid in transfer of antibiotic-resistant genetic elements. In eukaryotes, transposons can carry out...
02:02Cis-regulatory Sequences
Cis-regulatory sequences are short fragments of non-coding DNA that are present on the same chromosomes as the genes that they regulate. These fragments serve as binding sites for transcriptional regulators, proteins that are responsible for controlling gene transcription and differential gene expression across cell types in eukaryotes. Cis-regulatory sequences can be close to the gene of interest or thousands of bases away in the DNA sequence; however, those sequences that are further away are...
02:57DNA-only Transposons
DNA-only transposons are called autonomous transposons since they code for the enzyme transposase that is required for the transposition mechanism. Insertion of transposons can alter gene functions in multiple ways. They can mutate the gene, alter gene expression by introducing a novel promoter or insulator sequence, introduce new splice sites, and change the mRNA transcripts produced, or remodel chromatin structure.
The donor site from where the transposon is excised is either degraded or...
The donor site from where the transposon is excised is either degraded or...
03:18Non-LTR Retrotransposons
As the name suggests, non-LTR retrotransposons lack the long terminal repeats characteristic of the LTR retrotransposons. Additionally, both LTR and non-LTR retrotransposons use distinct mechanisms of mobilization. Non-LTR retrotransposons are further divided into two classes - Long interspersed nuclear elements (LINEs) and short interspersed nuclear elements (SINEs), both of which occur abundantly in most mammals, including humans. Some of the active non-LTR retrotransposons in humans are L1...
02:54Evolutionary Relationships through Genome Comparisons
Genome comparison is one of the excellent ways to interpret the evolutionary relationships between organisms. The basic principle of genome comparison is that if two species share a common feature, it is likely encoded by the DNA sequence conserved between both species. The advent of genome sequencing technologies in the late 20th century enabled scientists to understand the concept of conservation of domains between species and helped them to deduce evolutionary relationships across diverse...
03:08LTR Retrotransposons
LTR retrotransposons are class I transposable elements with long terminal repeats flanking an internal coding region. These elements are less abundant in mammals compared to other class I transposable elements. About 8 percent of human genomic DNA comprises LTR retrotransposons. Some of the common examples of LTR retrotransposons are Ty elements in yeast and Copia elements in Drosophila.
The internal coding region of LTR retrotransposons and their mechanism of transposition closely resembles a...
The internal coding region of LTR retrotransposons and their mechanism of transposition closely resembles a...