The photosynthetic sea slug, Plakobranchus ocellatus type black, (left) and an electron micrograph displaying sequestered algal chloroplasts within a sea slug cell (right).
One of the strongest arguments against intelligent design in nature is the example of stupidity to be found in the many ludicrously complex solutions to problems that should have been simple for an omniscient, omnipotent creator.
I spell out several examples of this in my popular book, Unintelligent Design: Refuting the Intelligent Design Hoax. Creationists have been fooled into believing that complexity is evidence for design, not against it, even though one of the basic principles of good design is minimal complexity and maximal simplcity. Complexity should be the minimum sufficient to achieve the design purpose, since anything more wastes resource and adds to the production cost while adding nothing it terms of utility value.
And here we have another example of this unnecessary complexity in nature, when a simpler solution was readily available.
To an admirer of the breath-taking inventiveness of the mindless, evolutionary process as it responds to environment change and opportunity to come up with novel solutions to problems, this takes some beating, because evolution is a mindless, utilitarian process where good design doesn't feature and working, sub-optimal solutions are often retained. The puzzle was how the photosynthetic capability of the ingested chloroplast is maintained in the sea slug when they ingest none of the algal nuclear DNA intact. Algal chloroplasts normally depend on algal nuclear genes to complete their photosynthesis since these have been transferred to the algal nucleus over the course of evolution. For this reason, algal chloroplasts removed from algal cells instantly lose their photosynthetic ability. However, they retain it in sea slug cells. The scientists have now sequenced the sea slug genome and shown that it contains none of the genes one would expect if horizontal gene transfer had occurred.
The actual mechanism of how photosynthesis is retained thus remains elusive, but the answer is not one of simple gene transfer and is almost certainly even more complex than that possible solution. The research has, however, yielded several clues that are being investigated further.
This example came too late for inclusion in my book, but there are few better examples of this principle of needless complexity on a massive scale to be found in nature. Basically, if you believe in intelligent [sic] design, you have to believe that when your putative designer decided the sea slug it had designed could be improved with the ability to produce energy by photosynthesis, like green plants, algae and some bacteria can, this is the solution it came up with, rather than by just giving them chloroplasts or the necessary structures and genes that plants, algae and some bacteria have.
Since the sea slug is a non-model organism, its genome analysis was very tough in comparison to model organisms such as the mouse and the fruitfly. Furthermore, there was no high-quality genetic information for them. This situation consequently hindered the verification of the hypothesis of algae-derived horizontal gene transfer. But we succeeded in accurately revealing the genome information of the sea slug.
We looked at the genome very carefully, but we found no evidence of photosynthetic genes encoded on the sea slug genome.
The discovery was made by scientists from the Japanese National Institute for Basic Biology (NIBB), who have gone some way towards solving the problem of just how sea slugs manage to retain the chloroplasts they 'steal' from the algae they eat in an active state for several months, apparently without any significant horizontal gene transfer. As the NIBB news release explains:
We looked at the genome very carefully, but we found no evidence of photosynthetic genes encoded on the sea slug genome.
Shuji Shigenobu, Co-corresponding author
Professor at National Institute for Basic Biology
Okazaki, Japan.
Professor at National Institute for Basic Biology
Okazaki, Japan.
A team of researchers at the National Institute for Basic Biology (NIBB), in addition to collaborators from seven other Japanese institutions, have published the genome of the sea slug, Plakobranchus ocellatus type black, in eLife. “Since the sea slug is a non-model organism, its genome analysis was very tough in comparison to model organisms such as the mouse and the fruitfly. Furthermore, there was no high-quality genetic information for them. This situation consequently hindered the verification of the hypothesis of algae-derived horizontal gene transfer," said Shuji Shigenobu, a genome scientist and professor at NIBB who is the corresponding author of the paper, "But we succeeded in accurately revealing the genome information of the sea slug". Scientists are ready to settle the arguments concerning the horizontal transfer of algal genes to the animal nucleus based on newly unveiled genome data. "We looked at the genome very carefully, but we found no evidence of photosynthetic genes encoded on the sea slug genome," he said.The Japanese team's findings are published, open access, in eLife Evolutionary Biology:
We are embarking upon a new challenge to answer the question: how does the sea slug retains this function without horizontal gene transfer? Our genome data also provides clues to this. We have found several candidate genes related to the long-term maintenance of photosynthetic activity. These genes related to protein metabolism, oxidative stress tolerance, and innate immunity should be subsequently highlighted in future studies."We are embarking upon a new challenge to answer the question: how does the sea slug retains this function without horizontal gene transfer?”, said Taro Maeda, the first and co-corresponding author of the paper. "Our genome data also provides clues to this. We have found several candidate genes related to the long-term maintenance of photosynthetic activity. These genes related to protein metabolism, oxidative stress tolerance, and innate immunity should be subsequently highlighted in future studies.”
Taro Maeda, the first and co-corresponding author
National Institute for Basic Biology,
Okazaki, Japan
The mechanisms underlying kleptoplasty are still elusive. Further understanding of this phenomenon may lead us to innovative biotechnologies, which, for example, could bestow photosynthetic abilities to other various animal cells in the future.
AbstractSo, not only did Creationism's putative intelligent [sic] designer fail to use a readily available solution to this problem of its own making (simply giving the sea slug the same organelles it gave plants) it also missed a trick in that it failed to use a slightly less complex solution which it has allegedly used several times in other species to give them the abilities normally possessed by an unrelated species - horizontal gene transfer. Instead, it has gone for something even more complex which has not been discovered yet. Maybe it hid it well through embarrassment!
Some sea slugs sequester chloroplasts from algal food in their intestinal cells and photosynthesize for months. This phenomenon, kleptoplasty, poses a question of how the chloroplast retains its activity without the algal nucleus. There have been debates on the horizontal transfer of algal genes to the animal nucleus. To settle the arguments, this study reported the genome of a kleptoplastic sea slug, Plakobranchus ocellatus, and found no evidence of photosynthetic genes encoded on the nucleus. Nevertheless, it was confirmed that light illumination prolongs the life of mollusk under starvation. These data presented a paradigm that a complex adaptive trait, as typified by photosynthesis, can be transferred between eukaryotic kingdoms by a unique organelle transmission without nuclear gene transfer. Our phylogenomic analysis showed that genes for proteolysis and immunity undergo gene expansion and are up-regulated in chloroplast-enriched tissue, suggesting that these molluskan genes are involved in the phenotype acquisition without horizontal gene transfer.
Maeda, Taro; Takahashi, Shunichi; Yoshida, Takao; Shimamura, Shigeru; Takaki, Yoshihiro; Nagai, Yukiko; Toyoda, Atsushi; Suzuki, Yutaka; Arimoto, Asuka; Ishii, Hisaki; Satoh, Nori; Nishiyama, Tomoaki; Hasebe, Mitsuyasu; Maruyama, Tadashi; Minagawa, Jun; Obokata, Junichi; Shigenobu, Shuji
Chloroplast acquisition without the gene transfer in kleptoplastic sea slugs, Plakobranchus ocellatus
eLife 2021;10:e60176 DOI: 10.7554/eLife.60176
Copyright: © 2021 The authors. Published by eLife Sciences Publications Ltd.
Open access
Reprinted under a Creative Commons Attribution 4.0 International License (CC BY 4.0)
And still Creationists continue to point to complexity as evidence of intelligent [sic] design while ignoring the abundant evidence that there was no design, intelligent or otherwise, in living organisms.
Complexity is evidence of poor design, not intelligent design.
Good design is simple, not complex.
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Good design is simple, not complex.
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