Unintelligent Design
Crazy Sex Determination in Male Yellow Crazy Ants
Crazy Sex Determination in Male Yellow Crazy Ants
A male yellow crazy ant (Anoplolepis gracilipes)
Photo/©: Hugo Darras
Male yellow crazy ants are real-life chimeras | Press and Public Relations
Two male yellow crazy ants (Anoplolepis gracilipes)
Photo/©: Hugo Darras
Not if you're the creationist cult's putative intelligent designer, you don't. What you do is come up with an even more complex way of doing the same thing, for no apparent benefit!
In many insects, including the hymenopterans (bees, wasps, ants, and sawflies) the normal way the sex of an individual is determined is by the number of copies of each chromosome in the cell nucleus. Females are diploid, i.e., they get two copies - one from their mother and one from their father, via a fertilized egg - while males are haploid, having only one copy, which they inherit from their mother via an unfertilized egg.
It has been that way since the order evolved, or so it would seem as almost all of them use the same method, suggesting it was the method used by their last common ancestor, 200 million years ago.
Hymenoptera is an order of insects that includes bees, wasps, ants, and sawflies. Fossil evidence suggests that the Hymenoptera evolved in the Late Triassic period, about 200 million years ago.
One of the earliest known hymenopterans is the family Xyelidae, represented by the species Xyela jurassica, which is known from a fossil discovered in the Jurassic Daohugou Beds of northeastern China. Another early hymenopteran is the family Praesiricidae, represented by the species Praesiricidae tenuipes, which is known from a fossil discovered in the Early Cretaceous Yixian Formation of northeastern China.
A comprehensive review of the evolution and phylogeny of Hymenoptera was published by Sharkey et al. in 2012 in the Annual Review of Entomology. The authors discuss the major lineages of Hymenoptera and their relationships based on molecular and morphological data.
Reference:
Sharkey, M. J., Carpenter, J. M., Vilhelmsen, L., Heraty, J., Liljeblad, J., Dowling, A. P., ... & Zaldívar-Riverón, A. (2012). Phylogenetic relationships among superfamilies of Hymenoptera. Annual Review of Entomology, 57, 49- 68. doi: 10.1146/annurev-ento-120710-100450.
ChatGPT. (2023). When did hymenopterans evolve? [Response to a question]. Retrieved from https://github.com/chatgpt/chat-gpt3
In Hymenopterans, the determination of gender (sex) is often associated with haplodiploidy, a unique sex determination system where males develop from unfertilized eggs, which only carry one set of chromosomes (haploid), and females develop from fertilized eggs, which carry two sets of chromosomes (diploid). In haplodiploid Hymenopterans, including bees, wasps, and ants, females are diploid and develop from fertilized eggs, while males are haploid and develop from unfertilized eggs. The haploid eggs develop into males because they only have one set of chromosomes, which means that they inherit all their genes from their mother. In contrast, diploid eggs that receive genetic material from both parents develop into females.
There are some exceptions to this pattern, however. Some Hymenopteran species, such as the parasitic wasps in the family Chalcididae, have a different sex determination system where females are haploid and males are diploid.
It is worth noting that not all Hymenopterans exhibit haplodiploidy, and some species have other sex determination systems. For example, in the sawfly family Pergidae, gender is determined by genetic factors on sex chromosomes, like in humans and many other animals.
Reference:Beukeboom, L. W., & van de Zande, L. (2010). Genetics of sex determination in the Hymenoptera. Annual review of genetics, 44, 71-92. doi: 10.1146/annurev-genet-102209-163723.
ChatGPT. (2023). How is gender determined in hymenopterans? [Response to a question]. Retrieved from https://github.com/chatgpt/chat-gpt3
But, the yellow crazy ant, Anoplolepis gracilipes, does it differently.
The males of this species have two sets of chromosomes, but just not in the same cell. It is technically a chimera, having some cells with a genome derived from its mother and other cells with a genome derived from its father. It develops from a fertilized egg, but unlike a normal fertilized egg, the sperm nucleus and the egg nucleus don't fuse but remain separate, so when the egg undergoes mitosis, one cell gets a 'male' genome and the other cell, a 'female' genome. (by 'male and 'female' genomes, I mean genomes derived from the father and mother respectively). From then on, it is a matter of random chance which daughter cell gets which genome as the developing embryo differentiates into the different specialized cells that make up the final adult.
This was discovered by a team led by Dr. Hugo Darras, Assistant Professor at Johannes Gutenberg University (JGU), Mainz, Germany, with colleagues from University of Lausanne, Lausanne, Switzerland, Valaya Alongkorn Rajabhat University, Pathum Thani, Thailand, and Göttingen University, Göttingen, Germany.
The research is explained in a Johannes Gutenberg University news release:
The yellow crazy ant, or Anoplolepis gracilipes, has the infamous distinction of being among the worst invasive species in the world. However, this is not the reason for which this particular ant is studied by a team of international researchers. What interests them is how the insects reproduce, because males of this ant have long perplexed scientists.The team's findings are the subject of a paper in Science:
The results of previous genetic analyses of the yellow crazy ant have shown that the males of this species have two copies of each chromosome. This was highly unexpected, as males usually develop from unfertilized eggs in ants, bees, and wasps – and thus should only have one maternal copy of each chromosome. With this in view, we decided to investigate this puzzling phenomenon with subsequent experiments.
We discovered that the male ants have maternal and paternal genomes in different cells of their body and are thus chimeras. To put it another way, all males have two genomes, but each cell of their bodies contains only one or the other of the two genomes.
Dr. Hugo Darras, lead author
Assistant Professor at Johannes Gutenberg University Mainz (JGU).
Two genomes in different cell clusters
The results were quite extraordinary. It had been assumed to date that the males of the yellow crazy ant carried the same two sets of chromosomes in all cells of their body. However, the team was able to demonstrate that this premise was anything but correct. Normally, in a multicellular life form – be this a human, a dog, or a bat – all cells contain identical genetic material.
The research team concludes that male yellow crazy ants are chimeras: they develop from fertilized eggs in which the two parental gametes do not actually fuse. Instead, the maternal and paternal nuclei divide separately within the same egg, meaning that the resultant adult males have both parental DNA sequences but in different body cells. When the gametes do fuse, either a queen or a worker develops from the egg, depending on the genetic information carried by the sperm. It is yet unknown what mechanisms determine whether fusion of the parental gametes takes place or not.
Chimerism and the yellow crazy ant: A mode of reproduction previously unknown to scienceIn contrast to these known cases, chimerism in the yellow crazy ant does not result from the fusion of two separate individuals or an exchange of cells between them. Instead, this process has its origin within a single fertilized egg. This is unique. Hence, the development of the male yellow crazy ant appears to contravene one of the fundamental laws of biological inheritance in which all cells of an individual should contain the same genome.
Dr. Hugo Darras
Chimeras are individuals whose cells contain different genetic materials. They naturally occur in certain species, such as corals and angler fish, in which separate individuals can merge to become one. Chimerism can also be found in humans and other placenta mammals. During gestation, mother and fetus can exchange a small number of cells so the offspring usually has a few cells that contain the same genetic material as the mother. Such small-scale exchanges also occur between twins in the womb.
A longitudinal section of the brain of a chimeric male yellow crazy ant with maternal (pink) and paternal (blue) genomes in situ hybridization: The male tissue consists of large cell clusters carrying only maternal or paternal genomes.Photo/©: Hugo Darras
Abstract
Multicellular organisms typically develop from a single fertilized egg and therefore consist of clonal cells. We report an extraordinary reproductive system in the yellow crazy ant. Males are chimeras of haploid cells from two divergent lineages: R and W. R cells are overrepresented in the males’ somatic tissues, whereas W cells are overrepresented in their sperm. Chimerism occurs when parental nuclei bypass syngamy and divide separately within the same egg. When syngamy takes place, the diploid offspring either develops into a queen when the oocyte is fertilized by an R sperm or into a worker when fertilized by a W sperm. This study reveals a mode of reproduction that may be associated with a conflict between lineages to preferentially enter the germ line.
Darras, H.; Berney, C.; Hasin, S.; Drescher, J.; Feldhaar, H.; Keller, L.
Obligate chimerism in male yellow crazy ants
Science, 380(6640), 55-58. DOI~; 10.1126/science.adf0419.
© 2023 The authors. Published by American Association for the Advancement of Science.
Reprinted with kind permission under license #5526740852228
Only creationism's putative intelligent designer can do such a convincing job of imitating a mindless, utilitarian natural process; a process that makes do if it works and which has no way of remembering what it did in another species, so continually re-invents the wheel, metaphorically speaking.
There are many ways in which sex is determined in nature, but this must be the most bizarre.
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