In my previous blog, I spoke about the Kinship theory. This theory states that the more relatedness there is between a group of individuals, the more likely to exhibit altruistic behavior the individuals are to be. Honeybee sisters share 75% of the same genetic material. This genetic similarity is what drives the honeybees to take care of the social group above the care of themselves.
Going back to high school biology, we know we are all comprised of segments of DNA. This DNA contains all of the genetic material that was handed down from our parents. As humans, we are Diploids. We get half of our chromosomes from our mother and half from our father. In total, humans have 46 Chromosomes (23 pairs). 22 of these pairs are autosomes (look the same in males and females), and the last one is a sex chromosome.
Of each of the sets of chromosomes we get from our parents, 50% of the material handed down from each parent is a copy of their genetic makeup. The other 50% are random combinations of genes (Mendell’s Law of Independent Assortment) that come together during meiosis. Meiosis is reduction division. From each parent, we get 1 set of chromosomes. During meiosis, the parental cells are divided by half so that in each egg and each sperm, there is only one set of chromosomes that will be paired together to form offspring.
Genes are distinct sequences of nucleotides forming parts of these chromosomes, and Alleles are specific forms or variants of genes located at specific positions on specific chromosomes. Different Alleles result in the different traits we exhibit. We get one Allele from each parent. That makes up the genotype. One of the Alleles we receive will be dominant and the other recessive. The dominant Allele is what will show up. This is called a phenotype. An example would be eye color. If our mother passed on a blue eye color recessive gene and our father passed on a brown eye dominant gene, even though we have both allele’s, we will have brown eyes.
Honey Bee Genetics
Honeybees have 32 Chromosomes. They get 16 from their mother (the Queen), and 16 from their father. The Drone is haploid, and only carries one set of chromosomes he received from his mother. The drones sperm does not undergo reduction division, therefore, the Drone passes on 100% of his genetic material to his daughters. The Queen, however, had a mother and a father, and during meiosis, her cells do undergo reduction division. Therefore, she passes 50% of her genetic material.
Here is a visual representation:
As you can see from the charts above, the worker bees share 25% of their mother’s genetic makeup, and 100% of their fathers. This makes them 75% related.
The Queen mates with an average of 15 Drones. Each egg she decides to fertilize gets a sperm donated from her spermatheca. So there will only be one Maternal genetic line in a hive (unless there has been a queen replacement), however there may be multiple paternal genetic lines.
If you look closely at the picture above, you can see different traits exhibited. There are bees with a dark colored abdomen like Carniolan, and lighter Italian bees.