How closely related are the genes on a single chromosome?

I doubt that a lone gene determines a trait or characteristic. As you suggest, a number of select genes, using information transferred by proteins, express or repress traits. Some of the select may be influenced by other genes that the environment activates, and in this way traits are dependent upon both genetic codes and the physical reality. If we knew that a specific gene, either failing to be expressed or being prematurely expressed, resulted in undesirable circumstances, and we were able to replace that gene, why swap chromosomes?

Genes are widely distributed across the 23 chromosomes. Between genes which are meaningful sequences of that code for the production of one of various types of proteins. Some are enzymes while some contribute to the formation of structures. Between the genes are what seems to be junk sequences. Our phenotype (how we are formed and how our bodies function) are influenced by many genes that are rarely near each other on the same chromosome and are often on entirely different chromosomes. (I worked as a post-doctoral research consultant in human genetics and medical genetics for over 12 years).

Thanks. I am truly amazed by what has been discovered by geneticists. It would be difficult enough if everything was on a macroscopic level – figuring out not only the sequencing but also the 3 dimensional shape of the molecules and how they interact.

While I have your attention, do geneticists have any idea of how new genes enter the genome? I can conceptualize mutation of existing genes, but how do you get a pair of new genes on a pair of chromosomes and how does the pair of genes manage to act in tandem?

My biochemist friend told me about how Evolutionary Biologists are able to track divergences in evolution through DNA studies. Blew me away because I thought you could only track evolution through fossil records (dead things). So evidence is available in CURRENTLY living organisms too.

It’s important to first understand what a Chromosome is and also the function and storage of DNA

Some long held conclusions concerning the evolution of species based upon the study of fossils have been overturned by the comparison of DNA and associated proteins sequenced on chromosomes.