Nucleus-what still needs to be discovered?

Some of the current research involves the three-dimensional organization of the chromosomes within the nucleus. We used to think that the decondensed chromosomes are simply piled in there like a big plate of spaghetti, but it now appears that there are organized regions within the nucleus where certain groups of proteins are found. Some genes are always found associated with the nuclear envelope, while others are found in various other parts of the nucleus. So it looks like this messy pile of spaghetti is actually organized in some way. People are still trying to work out the rules and principles governing this organization.