I just came across a very interesting article that talks about essential gene clusters and some speculation from a lab out of the Baylor College of Medicine.
Scientists say they found a cluster of essential genes on mouse chromosome 11, which is also found to be conserved in other organisms including humans, possum, cow, dog and chimp.
“When we saw that there were all these essential genes in this region, we wondered if the reason that the chromosome remained together (and is not easily broken apart or recombined with other parts of this or other chromosomes) is that it had all these densely packed essential genes. The reason this part of the chromosome has remained intact is that it has densely packed essential genes. If the chromosome broke anywhere, the organism would not develop,” said Dr. Monica Justice, the associate professor of molecular and human genetics at Baylor.