The presentation concludes with the goals for the comparative analysis of four Drosophila species where the F Elements have undergone different levels of expansion, and a summary of the unusual features (e.g., expansion of coding spans, pseudogene clusters) that have been identified by GEP students as part of their annotations of the D. melanogaster and in other Drosophila species based on past studies by the Elgin Lab, GEP faculty and students, and other researchers (e.g., the modENCODE project). The lecture then presents the unusual characteristics of the Muller F Elements in D. The lecture begins with a brief overview of the C-value paradox, the impact of transposable elements on eukaryotic genomes, and the packaging of DNA into chromatin. Louis describes the research aims for the Drosophila F Element Expansion project. In this lecture for the July 2022 GEP New Member Training, Professor Sarah C. The same material is covered in more detail in the “ Annotated Lecture Slides.” Introduction to the F Element Project provided by Dr.

We anticipate that this work will move us toward a better understanding of how and why eukaryotic genomes became so large, for mammals, ~1000X larger than that of E. (Euchromatic regions have not expanded in these species.) Comparative analyses using these datasets will provide insights into the evolutionary impacts of changes in chromosome and gene size, and will facilitate the identification of factors that enable genes to function in a heterochromatic environment. takahashii, as well as for genes in a euchromatic reference region derived from the Muller D element. GEP students will produce coding region and transcription start site annotations for F element genes in D. This study will examine the factors (e.g., transposon density) that have contributed to the expansion of the F element in these four Drosophila species, and assess the impact of this expansion on gene characteristics (e.g., codon bias, intron size). ananassae Muller F element is more than 18.7 Mb in size. While the F element has maintained a similar size in many other Drosophila species, it is substantially larger in at least four Drosophila species (i.e., D. These F element genes exhibit a range of expression levels similar to genes that reside in euchromatic domains - indicating that F element genes have acquired distinct features that enable them to function in a heterochromatic environment (reviewed in Riddle and Elgin, 2018). : Fluorine F 75.98 Element Cube Pure 25.4mm Density Cube for Element Collection Periodic Table Hunter, and More (1, Fluorine) : Industrial. However, the banded portion (~1.4 Mb) of this chromosome also contains ~80 protein-coding genes. melanogaster F element is generally packaged as heterochromatin: it has a high repeat content, is packaged throughout with HP1a and H3K9me2/3 it exhibits late replication and little or no recombination. The smallest chromosome in Drosophila melanogaster is chromosome 4 (also known as the Muller F element), with an estimated size of ~5.2 Mb ( Locke and McDermid, 1993).

One of the unusual features of eukaryotic genomes is the discordance between genome size and the complexity of the organism (i.e., the C-value paradox Eddy, 2012).