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Lateral gene transfer from protists could enable freshwater sponges to adapt to hypoxia

Vizitiu, Mara (2022) BINP52 20212
Degree Projects in Bioinformatics
Popular Abstract
Breathing without oxygen: Lateral gene transfer from protists could enable freshwater sponges to adapt to hypoxia

As humans, our existence is conditioned by oxygen. The complex mechanisms that keep our cells alive and functioning depend on this molecule and our metabolic processes would not be possible without it. Although we could not even survive in environments without oxygen, some organisms have evolved strategies to thrive in these unwelcoming conditions.

Our world is populated by diverse organisms, ranging from the smallest bacteria to unicellular eukaryotes, to animals. Throughout this wide diversity, many species have found strategies to conquer challenges encountered in their environments, survive, and reproduce. If we refer... (More)
Breathing without oxygen: Lateral gene transfer from protists could enable freshwater sponges to adapt to hypoxia

As humans, our existence is conditioned by oxygen. The complex mechanisms that keep our cells alive and functioning depend on this molecule and our metabolic processes would not be possible without it. Although we could not even survive in environments without oxygen, some organisms have evolved strategies to thrive in these unwelcoming conditions.

Our world is populated by diverse organisms, ranging from the smallest bacteria to unicellular eukaryotes, to animals. Throughout this wide diversity, many species have found strategies to conquer challenges encountered in their environments, survive, and reproduce. If we refer specifically to eukaryotes that can survive in low-oxygen conditions, adaptations to anaerobiosis can be found in representatives of most major groups. But although the end goal is similar, the strategies by which distinct organisms survive in low-oxygen (hypoxic) conditions differ greatly.

In this wide diversity, is it possible that different groups of organisms have “learned” and “borrowed” anaerobic adaptations from each other?

The gene they keep on giving
One known strategy that microbial eukaryotes (protists) use to adapt to hypoxia involves primarily the enzymatic product of a single gene that has been acquired from bacteria. This gene is called rqua and its product is responsible for synthesizing one of the important molecules of the anaerobic respiratory chain called “rhodoquinone”. Some animals, like parasitic worms, can also make rhodoquinone but do so through a more complex metabolic pathway. However, there are other animals that can live without oxygen – such as sponges – but the underlying mechanisms that facilitate their survival in these environments are unknown.

In my project, I investigated genetic data of several species of freshwater sponges and was able to identify rqua in three such datasets. Moreover, based on phylogenetic results, it appears that this gene is closely related to its homologue in the protistan group known as Euglenida. Such results can be easily disregarded as contaminations of the data. However, in this case, I was unable to find any clues suggesting that the data has been contaminated. Therefore, my results indicate that freshwater sponges have acquired a protist-specific gene through a process known as lateral gene transfer. This strategy of adapting to anaerobiosis has been passed on from bacteria to protists, and now to some of the oldest animal representatives, sponges. Having encountered significant drops in atmospheric oxygen concentrations approximately 200 million years ago, it is possible that acquiring this gene could have allowed the ancestor of freshwater sponges to survive these conditions and continue evolving into the species populating our planet today.

Master’s Degree Project in Bioinformatics 60 credits 2022
Department of Biology, Lund University

Advisor: Courtney Stairs
Department of Biology, Lund University (Less)
Please use this url to cite or link to this publication:
author
Vizitiu, Mara
supervisor
organization
course
BINP52 20212
year
type
H2 - Master's Degree (Two Years)
subject
language
English
id
9103405
date added to LUP
2022-11-21 16:22:56
date last changed
2022-11-21 16:22:56
@misc{9103405,
  author       = {{Vizitiu, Mara}},
  language     = {{eng}},
  note         = {{Student Paper}},
  title        = {{Lateral gene transfer from protists could enable freshwater sponges to adapt to hypoxia}},
  year         = {{2022}},
}