How to represent gene cytological location on chromosome

This video consist that how we can represent gene on particular chromosome. With the help of this video you can easily locate and identify a gene location on chromosome.

[@prateek_.a]

Excellent explanation 👏🏻👏🏻👏🏻

[@gemini7902]

Thank you ma'amm

[@sonudas837]

Good explanation..but how region 1is related with dark/light portion...and what if it is 2...3..so on