Male yellow crazy ants are real-life chimeras

Date:
April 11, 2023
Source:
Johannes Gutenberg Universitaet Mainz
Summary:
Researchers discovered that males of the yellow crazy ant have
maternal and paternal genomes in different cells of their body
and are thus chimeras.


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FULL STORY ==========================================================================
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 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," explained Dr. Hugo Darras, Assistant Professor at Johannes Gutenberg University Mainz (JGU) and lead author of the corresponding article recently published in Science. "With
this in view, we decided to investigate this puzzling phenomenon with subsequent experiments."

==========================================================================
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. "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," summarized Darras. 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 science 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. "In 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," concluded Darras. 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.

* RELATED_TOPICS
o Plants_&_Animals
# Biology # Mating_and_Breeding # Biotechnology # Genetics
o Earth_&_Climate
# Exotic_Species # Earth_Science # Biodiversity
* RELATED_TERMS
o Bone_marrow o Stem_cell o Seahorse o White_blood_cell o
Spaying_and_neutering o Somatic_cell o Yellow_fever o Gene

========================================================================== Story Source: Materials provided by
Johannes_Gutenberg_Universitaet_Mainz. Note: Content may be edited for
style and length.


========================================================================== Journal Reference:
1. H. Darras, C. Berney, S. Hasin, J. Drescher, H. Feldhaar, L. Keller.

Obligate chimerism in male yellow crazy ants. Science, 2023; 380
(6640): 55 DOI: 10.1126/science.adf0419 ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2023/04/230411105912.htm

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