Novel or highly modified genes play a major role in the development of the different castes within ant colonies. Evolutionary biologists at Johannes Gutenberg University Mainz (JGU) came to this conclusion in a recent gene expression study.
A small colony of the Temnothorax longispinosus ant species with two queens
photo/©: Susanne Foitzik, JGU
Dr. Barbara Feldmeyer and her colleagues at the JGU Institute of Zoology studied the question how the different female castes arise. An ant colony generally consists of a queen and the workers. Moreover, workers can differ depending on the task they perform, such as brood care, foraging, or nest defense.
This behavioral specialization may be accompanied by morphological and physiological differences. Queens, solely responsible for reproduction, can live up to 30 years while workers have life spans ranging from a few months to several years. In some species there are also soldier ants, which can weigh up to 100 times more than their worker sisters who take care of the brood.
Interestingly, the divergent phenotypic traits of queens and workers develop from the same genetic background; the different phenotypic trajectories are determined by the food larvae receive during development. Usually the queen is the sole reproductive individual in a nest but if she dies or is removed, some brood-care workers will develop their ovaries and begin to reproduce.
It was this phenomenon that the Mainz scientists exploited in order to induce fertility in brood-care workers of the Temnothorax longispinosus ant species. This allowed the comparison of these fertile workers with infertile brood-carers, foragers, and the queens to determine the expression of genes causing the enormous variations in behavior, fertility, and life span.
"We have here the ideal model system to study polyphenism, which describes the situation in which one and the same genotype gives rise to phenotypes that differ in terms of individual morphology, behavior, and life history," said Dr. Barbara Feldmeyer. Each sample used for RNA sequencing encompassed up to 100 million reads, i.e., short sequence sections of about 100 base pairs. The largest differences in gene expression were found between the queen and the worker castes, while the smallest differences were determined between the infertile brood carers and the foragers. The fertile brood care workers occupy an intermediate position between the queen and the sterile workers.
The ant queens expressed many caste-specific genes whose functions were known from comparisons with other species. This is not the case for the workers in which about half of the characteristic genes were found to be of unknown function. "Either these worker genes have undergone major modifications or they are novel genes," explained Feldmeyer. The fact that queens express more genes known from solitary hymenopterans and other insects fits to the evolution of social insects with workers being the derived state.
"This study of the differences in gene expression among ant castes is characteristic of the enormous advances that are currently being made in the field of biology," explained Professor Susanne Foitzik, head of the Evolutionary Biology work group at Mainz University. RNA sequencing is a technique that enables scientists to gain in-depth molecular information even for organisms that are not among the standard biological model organisms, such as the fruit fly Drosophila. "We can now also look at species known for their complexity in social behavior. In addition, by studying ants we can gain insights into the genes that are responsible for the unusually long life and fertility in insect queens," added Foitzik. The work group plans to continue its research into this area under the aegis of the new GeneRED research unit of the Faculty of Biology and the Institute of Molecular Biology (IMB).Image:
Petra Giegerich | idw
Two Group A Streptococcus genes linked to 'flesh-eating' bacterial infections
25.09.2017 | University of Maryland
Rainbow colors reveal cell history: Uncovering β-cell heterogeneity
22.09.2017 | DFG-Forschungszentrum für Regenerative Therapien TU Dresden
At the productronica trade fair in Munich this November, the Fraunhofer Institute for Laser Technology ILT will be presenting Laser-Based Tape-Automated Bonding, LaserTAB for short. The experts from Aachen will be demonstrating how new battery cells and power electronics can be micro-welded more efficiently and precisely than ever before thanks to new optics and robot support.
Fraunhofer ILT from Aachen relies on a clever combination of robotics and a laser scanner with new optics as well as process monitoring, which it has developed...
Plants and algae use the enzyme Rubisco to fix carbon dioxide, removing it from the atmosphere and converting it into biomass. Algae have figured out a way to increase the efficiency of carbon fixation. They gather most of their Rubisco into a ball-shaped microcompartment called the pyrenoid, which they flood with a high local concentration of carbon dioxide. A team of scientists at Princeton University, the Carnegie Institution for Science, Stanford University and the Max Plank Institute of Biochemistry have unravelled the mysteries of how the pyrenoid is assembled. These insights can help to engineer crops that remove more carbon dioxide from the atmosphere while producing more food.
A warming planet
Our brains house extremely complex neuronal circuits, whose detailed structures are still largely unknown. This is especially true for the so-called cerebral cortex of mammals, where among other things vision, thoughts or spatial orientation are being computed. Here the rules by which nerve cells are connected to each other are only partly understood. A team of scientists around Moritz Helmstaedter at the Frankfiurt Max Planck Institute for Brain Research and Helene Schmidt (Humboldt University in Berlin) have now discovered a surprisingly precise nerve cell connectivity pattern in the part of the cerebral cortex that is responsible for orienting the individual animal or human in space.
The researchers report online in Nature (Schmidt et al., 2017. Axonal synapse sorting in medial entorhinal cortex, DOI: 10.1038/nature24005) that synapses in...
Whispering gallery mode (WGM) resonators are used to make tiny micro-lasers, sensors, switches, routers and other devices. These tiny structures rely on a...
Using ultrafast flashes of laser and x-ray radiation, scientists at the Max Planck Institute of Quantum Optics (Garching, Germany) took snapshots of the briefest electron motion inside a solid material to date. The electron motion lasted only 750 billionths of the billionth of a second before it fainted, setting a new record of human capability to capture ultrafast processes inside solids!
When x-rays shine onto solid materials or large molecules, an electron is pushed away from its original place near the nucleus of the atom, leaving a hole...
19.09.2017 | Event News
12.09.2017 | Event News
06.09.2017 | Event News
25.09.2017 | Power and Electrical Engineering
25.09.2017 | Health and Medicine
25.09.2017 | Physics and Astronomy