Experimentally probing the origins of DNA
In modern cells, the precursors of DNA are produced from RNA precursors via an enzymatic reaction called ribonucleotide reduction. This suggests that DNA evolved after RNA, and in turn, that biological systems once relied on RNA as genetic material. Furthermore, because synthesis of deoxythymidine (dT) from deoxyuridine (dU) requires additional enzymatic steps, modern DNA appears to have evolved via two transitions, a first transition from RNA to DNA, then the replacement of U with T as fourth base. On paper, such transitions appear relatively straightforward, but, if these transitions occurred in earlier cellular lineages, it is possible that they were quite disruptive events. My lab has been attempting to probe the evolutionary events leading of modern DNA using a combination of synthetic biology tools and experimental evolution. The overall aim is to try study these proposed transitions, to assess whether they are plausible, and to attempt to create analogs of the ancestral state. To this end, I will present our ongoing work on constructing a uracil-DNA genome in the bacterium E. coli. I will also present our results on the direct detection of uracil incorporation into the genome of our bacterial lines using nanopore sequencing. I will outline our plans to test models for the UT transition and will also present ongoing work on evolving a bacterial lineage lacking ribonucleotide reduction.
|Date||Tuesday, 13 April 2021|
|Time||12:00pm - 1:00pm|
|Event Category||Health Sciences|
|Location||Biochemistry Seminar Room BIG13, Dunedin|
|Contact Name||Department of Biochemistry|
|Contact Phone||+64 3 479 7863|