Circadian rhythm gene in mice discovered

There is a single gene that if disrupted will kill your circadian rhythm: Bmal1 aka Arntl. No other known gene has this property, but some combinations of other will do the same. https://en.wikipedia.org/wiki/ARNTL

If I had to guess there are probably way more genes/DNA elements controlling eye color than genes controlling circadian rhythms.

In some biological systems, just a handful of genes can make a circadian clock. For cyanobacteria, it's literally three proteins (KaiA, KaiB, KaiC) and the robust periodic phenomenon can be reconstituted in a test tube.

For mouse the current paradigm of the circadian clock involves a handful of genes (Figure 6 in their paper).

Randomly picking a gene and disrupting it most likely will not disrupt the circadian rhythm of the animal.

The novel finding in this paper is that they are proposing a new gene, one that does not code for a protein, seems to also regulate the circadian clock. This changes how we think of the circuit that wires the circadian clock.

I am impressed that this study took nine years. One must be deeply interested in the topic to sustain that type of effort for a story. I can imagine many scientists dropping the project long before nine years in search of lower hanging fruit.

So ... it's even less clear, but there are probably at least 10 or more genes involved, and if any of them is too broken you get some illness.

This is only one of the many genes involved in the circadian rhythm (in mice, and probably have an equivalent in humans). Each discovery is important and add some incremental amount of information, but usually the press article likes to make a groundbreaking discovery that solves all the related problems for ever.

It's more like "the gene of height", or "the gene of weight". Some features like eye color has only one gene (or one gene that is much more important than the others), but many other features involve a lot of genes.