Are crazy yellow ants so "crazy" because they have two sets of DNA?

There is a kind of yellow ant that makes some irregular movements when disturbed, so people nicknamed it "crazy ant", which is why the yellow crazy ant got its name. In April 2023, a study published in Science magazine found that there may be another reason why the yellow crazy ant is crazy - male and female yellow crazy ants are chimeras composed of somatic cells with different genetic backgrounds, and they are the first known animals to have this characteristic as a basic feature of life.

Normally, worker ants are haploid, developed from unfertilized eggs, and have only one set of genomes from the queen. In special cases, there are also very few male ants that are diploid, but this is usually a developmental accident and the ants are infertile. However, there are always surprises in diverse biological systems, and female yellow crazy ants are one of these surprises. Although their somatic cells are all haploid, they have two genomes. Some somatic cells only carry the R genome from the mother, and the other somatic cells only carry the W genome from the father.

In other words, the female yellow crazy ant also develops into a diploid organism. Humans, almost all higher animals, and more than half of higher plants are diploid.

Diploid organisms have certain survival advantages over haploid organisms because the latter only have one copy of a gene, and a mutation in a key gene may affect the survival of the organism. Diploid organisms have two copies of genes, and if one of the genes has a functional defect, the other intact gene can continue to work.

The yellow crazy ant is one of the most notorious invasive species. They have a strong reproductive capacity and can establish super colonies covering an area of ​​more than 150 hectares. They are also extremely destructive and can have a huge negative impact on local ecosystems. For example, Christmas Island in Australia is famous for its large-scale red crab migration, but the arrival of the yellow crazy ant has brought a catastrophe to this species, causing the death of 10 million to 15 million red crabs in severe cases.

The picture comes from Tuchong.com

Scientists have been trying to find biological methods other than spraying chemical pesticides to control the spread of yellow crazy ants. Studies have found that this unique chimera advantage may be the reason why yellow crazy ants are so crazy.

In nature, similar chimeras exist in only a few species, such as marmosets, which can form chimeras by exchanging stem cells through a shared placenta when conceiving fraternal twins. However, scientists have only discovered one animal, the yellow crazy ant, which forms chimeras from the single-cell embryo stage.

This study not only helps us once again understand the wonders of species diversity, but may also provide us with ideas for controlling the reproduction of yellow crazy ants in the future. However, there are still many unsolved mysteries waiting for people to explore about the unique reproduction method of female yellow crazy ants.

This article is a work supported by Science Popularization China Starry Sky Project

Author: Tiangeng

Reviewer: Tao Ning (Associate Researcher, Institute of Biophysics, Chinese Academy of Sciences)

Produced by: China Association for Science and Technology Department of Science Popularization

Producer: China Science and Technology Press Co., Ltd., Beijing Zhongke Xinghe Culture Media Co., Ltd.