Did Sea Slugs Evolve to Steal Genes? | The Institute for Creation Research

Did Sea Slugs Evolve to Steal Genes?

Solar-powered sea slugs (sacoglossan molluscs) feed on filamentous algae, a water plant, to capture photosynthetic organelles called chloroplasts and use them for solar energy. Considered kleptoplastic because they "steal" from another organism, sea slugs have been suspected of using horizontal gene transfer (HGT) to accomplish this, a find that many scientists believe would support evolution.

To keep the stolen chloroplasts alive and well inside the cells of their pervasive digestive tracts for several months at a time, sea slugs need the help of algal genes that code for important chloroplast maintenance proteins. Scientists first thought that these "algal genes" were stolen and integrated into the genome of the sea slug through HGT. In other words, they believed that at some point during the slug's evolution, it had somehow stolen just the right algae genes needed to make the stolen chloroplasts function.

Initial research seemed to show the presence of algal DNA in the slug genome, although the data was often conflicting and inconclusive.1 The problem was that scientists always used slug tissue to extract DNA that contained algal contamination.

In a new study, scientists extracted uncontaminated DNA from kleptoplastic sea slug eggs that had never come in contact with algae. After an exhaustive DNA sequencing process, the scientists concluded that the slugs and algae did not share any genes, and therefore the slugs had not acquired any algal genes through HGT.2

Some scientists believe that for evolution to be feasible, HGT has to have occurred on a grand scale among complex multicellular organisms like the solar-powered sea slug. In fact, the pervasive phenomena of large numbers of specific genes found in some organisms and not others (orphan genes) is believed to be explained by HGT. As this most recent sea slug study shows, these ideas have yet to be proven.3, 4

With the evolutionary explanation of HGT now shown to be completely lacking, what actually seems to be going on here? The scientists also tested adult sea slugs and found algal DNA in their system that encoded the genes necessary to make the chloroplasts work, and they concluded that the genes resided on extra chromosomal circular DNAs (eccDNAs). Surprisingly, eccDNAs are spliced out of a creature's genome, such as the algae, and formed into stable circles. In fact, eccDNAs of different types are found across the spectrum of life—even in humans!5

Could it be that the Creator designed the algae to not only provide chloroplasts for the sea slugs but also for the algal eccDNAs that contain the genes to make the whole living system work? In this scenario, both the chloroplasts and the eccDNAs would be extracted from the algae at the same time, and new genomics data indicates that this is likely the case. The sea slug is not an evolved kleptomaniac at all but a wonderfully engineered system co-designed with the algae.

References

  1. Pierce, S. K. et al. 2012. Transcriptomic evidence for the Expression of Horizontally Transferred Algal Nuclear Genes in the Photosynthetic Sea Slug, Elysia chlorotica. Molecular Biology and Evolution. 29 (6): 1545-1556.
  2. Bhattacharya, D. et al. 2013. Genome Analysis of Elysia chlorotica Egg DNA Provides No Evidence for Horizontal Gene Transfer into the Germ Line of this Kleptoplastic Mollusc. Molecular Biology and Evolution. 30 (8): 1843-1852.
  3. Tomkins, J. 2013. Newly Discovered 'Orphan Genes' Defy Evolution. Creation Science Update. Posted on icr.org August 26, 2013, accessed October 25, 2013.
  4. Tomkins, J. 2012. Are Rotifers Gene Stealers or Uniquely Engineered? Creation Science Update. Posted on icr.org December 3, 2012, accessed October 25, 2013.
  5. Shibata, Y. et al. 2012. Extrachromosomal MicroDNAs and Chromosomal Microdeletions in Normal Tissues. Science. 336 (6077): 82-86.

Image credit: Copyright © 2013 EOL Learning and Education Group. Adapted for use in accordance with federal copyright (fair use doctrine) law. Usage by ICR does not imply endorsement of copyright holders.

* Dr. Tomkins is Research Associate at the Institute for Creation Research and received his Ph.D. in genetics from Clemson University.

Article posted on November 6, 2013.

The Latest
NEWS
'Prehistoric' Paddlefish?
Evolutionists consider the freshwater paddlefish (Polyodon spathula) of the class Actinopterygii to be a prehistoric creature, a primitive bony fish “50...

ACTS & FACTS
Creation Kids: Earth
by Christy Hardy and Susan Windsor* You’re never too young to be a creation scientist! Kids, discover fun facts about God’s creation...

ACTS & FACTS
To the End of the Earth
The book of Acts recounts the apostles’ journeys across the Roman Empire from Jerusalem and Judea “to the end of the earth,” preaching...

APOLOGETICS
Lightning, Soil Bacteria, and God’s Providence
Nitrogen is vital for human survival, yet few appreciate how lightning and soil bacteria contribute to Earth’s nitrogen cycle. That Earth’s...

ACTS & FACTS
The Bobtail Squid's Living Cloaking Device
Hawaiian bobtail squid (Euprymna scolopes) live among the sand flats and sea plants of the Hawaiian archipelago. Along with other bobtail squid, these...

ACTS & FACTS
Seeing Distant Starlight in a Young Universe
Many see distant starlight as an unanswerable objection to recent creation. Both creationist and evolutionist astronomers agree that distant galaxies...

ACTS & FACTS
Yellowstone National Park, Part 2: Canyons and Catastrophe
by Tim Clarey, Ph.D., and Brian Thomas, Ph.D.* About three million visitors tour Yellowstone National Park’s 3,440 square miles each year.1...

ACTS & FACTS
How Did the Bat Get Its Wings?
Where did bats come from? Evolutionists presuppose that some kind of rodent received just the right mutations to over “a few million years”...

ACTS & FACTS
Biblical Insights into Today’s Violent Mob Mentality
Some scenes from the evening news get etched into our memories. I recall seeing a college professor step outside his building and become suddenly surrounded...

CREATION PODCAST
Are Dinosaurs in the Bible? | The Creation Podcast: Episode 26
If the Bible is true, wouldn't it mention dinosaurs? If God made dinosaurs, when did He make them? Did they live with humans? What ultimately happened...