Tuesday, February 12, 2013

The Haploid Prince

Identical twins are simultaneous clones, right? The fertilized cells, dividing and dividing, somehow divide into two batches and, instead of working together to create one human individual, work in parallel to make two. Simple minded science fiction stories have imagined clones as exact duplicates of an original. But a clone won’t be the same person. Identical twins, despite having grown from only one fertilized egg cell, end up being different people. They have a lot of similarities, and scientists are still studying identical twins to try to figure out which similarities are inherent in that original cell, but they are separate people.

I’ve heard that geckos can produce clones of themselves. A gecko egg does not need to be fertilized to develop into a normal gecko. A normal female gecko. Which is a clone of its mother.

When an ant queen lays eggs and female worker ants hatch from them, those eggs were fertilized by sperm from a male ant. During the future queen’s maiden – and conjugal – and only – flight, she mates with as many ant males as she can. She can store up sperm for years, using it judiciously to build up an ant city of her daughters. The ant queen also produces sons. But she doesn’t use sperm on the eggs that will hatch as sons. Her sons are her clones. Half-clones, actually.
Most animals, including humans, are diploid, which means that each of their cells contains two sets of chromosomes. When they make sperm and eggs, however, each sperm and egg contains only one chromosome set: when they are combined in the form of a fertilized egg, the animal will then be born with two sets of chromosomes. Males of bees and ants, however, are born as haploid animals, which means that each of their cells contains only a single set of chromosomes.

Cut a queen in half and she’s really a boy? It takes two kings to make a queen …

Which leaves me wondering about those geckos – are they all just a harem of haploids?

source: Secret Lives of Ants by Jae Choe