Research

Genomes are frequently in conflict with selfish DNAs – genetic elements that can spread in genomes and populations without offering any benefit, and many times even causing harm, to their hosts. Our lab integrates genomic, cytological and molecular approaches to study selfish DNA and its impact on genome evolution. Our primary interest is in satellite DNA (repetitive DNA typically found at centromeres and telomeres) and meiotic drive. Lab projects focus on three related areas:

 

I. The functional and evolutionary genomics of satellite DNA

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Drosophila melanogaster mitotic chromosomes labeled with a 1.688 family satellite probe.

Satellite DNAs are tandem repeats typically found at centromeres and telomeres. We use genomic, cytological and molecular approaches to study the functional genomics of satellite DNAs and their dynamic evolution across taxa.

 

 

 

II. Molecular mechanisms of meiotic drive

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A cyst of individualizing sperm in Drosophila affinis sex ratio males.

Meiotic drivers are selfish genetic elements that gain a transmission advantage through the germline. We use genetic, genomic and cytological approaches to determine the molecular mechanism of different drive systems. Our primary focus is on the selfish Segregation Distorter complex of D. melanogaster.

 

 

III. Y chromosome evolution

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Drosophila guanche mitotic chromosomes: sex chromosomes are labeled with an rDNA probe.

Drosophila Y chromosomes are dense in repetitive sequences and carry few protein-coding genes, but in most species are important for male fertility.  We are interested in the evolution of Y chromosomes across Drosophila species.

 

 

IV. Centromere evolution in Drosophila

The pileup of CENP-A (centromeric histone variant) ChIPseq reads on the complex island corresponding to the centromere on the 4th chromosome. Figure from Chang et al. 2019 bioRxiv
Centromeres are essential chromosomal regions required for proper chromosome segregation. We know little about the sequence and organization of most centromeres because they are embedded in large block of satellite DNA.  We recently discovered that Drosophila centromeres correspond to islands of retroelements embedded in satellite DNA, together with our collaborators. We study the evolution of centromere organization in Drosophila species.
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Photinus pyralis