The genetic material appearing like a thread in the nucleus is known as chromatin.

Here's a breakdown:

* Chromatin is the complex of DNA and proteins that make up chromosomes in eukaryotic cells. It's essentially the uncondensed form of chromosomes, which are only visible during cell division.

* Chromosomes are the tightly coiled and condensed structures of DNA that become visible during cell division.

* DNA (Deoxyribonucleic acid) is the genetic material that contains the instructions for building and maintaining an organism.

So, in the nucleus, DNA is normally present in the form of chromatin, giving it a thread-like appearance. During cell division, chromatin condenses into chromosomes.