The gana is not a description that stands on its own. It exists because it is one of the factors compared when two horoscopes are set beside one another in the ashtakuta method, the eight-part reckoning used across much of North Indian jyotisha to assess the fit between two people before a marriage. Gana kuta is one of those eight factors, and it is weighted at six points, among the heavier of the eight. The comparison is made not between the two people but between their birth nakshatras, and the gana of each nakshatra supplies the value.
Nine of the twenty seven nakshatras are assigned to deva gana: Ashwini, Mrigashira, Punarvasu, Pushya, Hasta, Swati, Anuradha, Shravana and Revati. The distribution is even, nine to each of the three ganas, and it does not follow the sign boundaries, so two people born under the same rashi may fall into different ganas and two born under different rashis may share one.
Two things are worth saying plainly about how this is used. The first is that gana kuta is one factor among eight and is not read alone; a practitioner weighing a match considers the whole set and the wider chart, and a single low score is not treated as decisive. The second is that this is living practice, carried out today by families and by professional jyotishis, not a historical curiosity. It is described here rather than recommended or instructed, and anyone wanting a reading of an actual chart should go to someone who does this work.