Not a scientist so I may be wrong in places, but here goes: A chromosome is DNA folded up. What was previously thought to be specks of dust on a microscope sli

Not a scientist so I may be wrong in places, but here goes: A chromosome is DNA folded up. What was previously thought to be specks of dust on a microscope slide turns out to be very small chromosomes. Their function is unclear. Between many birds and reptiles these microchromosomes seem to line up with the normal chromosomes fairly well. The difference is relatively speaking fairly small. In mammals however these microchromosomes are much more jumbled. These microchromosomes cluster together in the center of a cells nucleus. This means they physically interact. They touch. Now what this all means is as of yet not entirely clear. They most likely have some important function since they got preserved very well along evolution. Mammals however did something weird to these microchromosomes for unknown reasons.