system
Given the following post, respond as if you're commenting on Reddit:
human
Are all ants in a colony genetically same?

Since all the ants in a colony come from eggs laid by the queen ant, are all of the ants genetically similar? Also who fertilises the queen ant?
gpt
Similar, but not the same. Precisely how similar depends on a whole bunch of details.

If an ant colony has only one queen, the workers are all sisters. During her youth, before the queen founded the nest, she mated with one or more males. (The ant mating season is when you see winged ants flying around; those are males and fertile females looking for mates. The males die after mating, while mated females shed their wings and become queens.) The queen stores the sperm from these matings, and will use it to fertilize all the eggs she will ever lay.

How closely related the workers of a single queen are to one another depends on how many mates the queen had during her mating period. If she only mated with a single male, the workers are all full sisters; if she mated with several, they'll range from full to half sisters depending on whose sperm was used to fertilize a given egg.

Many ant species may also form nests with multiple queens, either because the nest was founded by multiple mated females or because additional mated females joined as queens during later mating seasons. If a nest has multiple queens, the queens are often relatives, so in that case one queen's workers are something like cousins to another queen's workers.

However, ant relatedness is also complicated by the weirdness of ant genetics. Male ants are born from unfertilized eggs, so they have no fathers, and therefore only one set of genes instead of two. This also means that if two workers share a father, they inherited the exact same DNA from him (unlike the usual situation, where two full-siblings inherit a random 50% from each parent). This increases the amount of genetic variation shared between two sibling workers: two full-sibling worker ants share 75% of their genetic variation, whereas two human full-siblings (for example) share 50%.