How does the chromosome theory of inheritance expand on what Gregor Mendle knew?

Answer 1

Hi Amelia L.,

So I don't believe Mendel (note spelling, please!) had a clue on chromosome numbers, or crossing over, or jumping genes. I'm not sure if he had an idea about traits determined by multiple genes (not just multiple alleles, that he knew), and autosomal vs. sex-linked traits. And very likely he had no idea about lethal recessives, either. Or interspecies hybrids.

But he hit the nail on the head with essential ideas of dominant and recessive genes/traits, and random assortment of chromosomes during sexual reproduction, and 2n (diploid) character of at least some plants (we do a lot now with polyploid crops; commercial lettuce and so on are bred polyploid for thicker leaves and stems, shorter internodes, and so on).

That's scratching the surface, anyway.

--Cheers, --Mr. d.