1.1 Introduction
Transposable elements are capable of switching their positions on the genome thereby causing gene arrangements and contributing to genome evolution. Transposable elements (TEs) are mobile DNA sequences that are able to move within genomes. TEs display great diversity and are ubiquitous in living organisms, which led researchers to study their involvement in genomics. Improvements in sequencing techniques and data analysis are making it easier to identify these elements in a wide range of organisms. Current genomic developments are providing useful tools for investigating the activity of TEs and determining their impact on genome shape. Transposable elements (TEs) comprise a major portion of many plant genomes and bursts of TE movements cause novel genomic variation within species.
As a prelude to other parts of this study, this chapter will discuss the background upon which this study was initiated, the statement of problems that led to this study, the Aim and Objectives of the study. Others are Significance of the study, Scope of work, Research hypothesis and questions, Limitations of the Study and Definition of technical terms.
1.2 Background of Study
Recent studies have correlated these transposition bursts with host lineage divergences in salmonids, bats and Drosophila. For instance, in the bat genus Myotis, the most diverse mammalian genus, repeated invasion of the Myotis genomes by transposons has been correlated with the wide genetic diversity associated with species divergence (Ray et al. 2008). The involvement of TEs in speciation mechanisms remains controversial within the scientific community, although a few examples definitely suggest that TEs might be involved in speciation events. Recent studies, particularly those carried out in plants; suggest that TEs probably are involved in species evolution (Tian et al. 2011, Levy 2013).
TEs are included in the repetitive DNA fraction that also contains endogenous retroviruses, tandem repeats and microsatellites. They can have diverse structures and, as such, no universal structural rule exists for their identification. The lack of general structural features makes them very difficult to identify. They are often detected on the basis of their similarity to and/or homology with established TEs, hence TEs with novel structures or carrying numerous mutations are still difficult to identify and classify. TE diversity and the frequent discovery of new elements make their classification challenging.
The commonly accepted classification is currently that proposed for eukaryotic TEs by Wicker et al. (2007). This bases the first level of classification on the presence or absence of an RNA transposition intermediate, with subsequent classification levels being determined by the mode of transposition, the insertion mechanism that leads to target site duplication (TSD) at the end of the insertion process, their structural organization and sequence homologies. Remnants have lost their ability to move as a result of sequence deletion or mutation, and only part of the original element is still present in genomes. They certainly constitute the bulk of TEs in genomes, but they are also the most difficult to estimate because they may be so mutated or deleted that they are no longer recognizable. Non-autonomous elements are composed of TEs that use the machinery of other TEs to transpose and replicate. The TEs that help non-autonomous elements to move are known as master elements (Feschotte & Mouchès 2000).
Therefore, in Nigeria where the research was carried out, the activities that was conducted is to know the Transposable Element in Bacterial Pathogenesis.
1.3 Statement of Problems
Investigation revealed that the lack of general structural features makes them very difficult to identify. They are often detected on the basis of their similarity to and/or homology with established TEs, hence TEs with novel structures or carrying numerous mutations are still difficult to identify and classify. TE diversity and the frequent discovery of new elements make their classification challenging.
1.4 Aim and Objectives of Study
The aim of the study is to examine the Transposable Element in Bacterial Pathogenesis. In achieving this aim, the following specific objectives were laid out as follows:
- To identify transposable elements in a wide range of organisms;
- To provide useful tools for investigating the activity of transposable elements; and
- To proffer the problems of the above stated problems.
1.5 Research Questions
The study came up with research questions so as to be able to ascertain the above stated objectives. The specific research questions for the study are stated below as follows:
- What are the transposable elements in a wide range of organisms?
- What are the useful tools for investigating the activity of transposable elements?
1.6 Significance of Study
This study will be of immense benefit to researchers who intend to know more on this study and can also be used by non-researchers to build more on their research work. This study contributes to knowledge and could serve as a guide for other study.
1.7 Scope of the Study
The scope of the research is focused on the Transposable Element in Bacterial Pathogenesis.
1.8 Limitations of the Study
During the course of this study, many things militated against its completion, some of which are:
- Time Constraint: The time frame given to accomplish this project was very short due to school academic calendar and it was carried out under pressure which made the researcher not to implement some necessary features.
- Research material: availability of research material is a major setback to the scope of the study.
- Frequent power failure: This made the researcher append more money on fuel to ensure sustainable power.
- Financial Constraint: Insufficient fund tends to impede the efficiency of the researcher in sourcing for the relevant materials, literature or information and in the process of data collection (internet, questionnaire and interview).
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