How do u know if two genes on Drosopila are independent or linked& if linked, how can u get the distance?

I mean how can u get the distance for linked genes for the the Carolina crossses? i would really appreciate the help. Tanx!

How do u know if two genes on Drosopila are independent or linked%26amp; if linked, how can u get the distance?
the data will lead u...the frequency of genes traveling together increase as the genes are physically closer together...thus if two genes follow Mendelian genetics then they are not linked because they are not close to each other physically....but u can read this in the bible...its God's plan...he created us...it says so in the bible and therefore it must be true...