Question

. In order for Mendelian genetics to hold true, what assumptions must be made?

Answer 1

Mendilian genetics considers genes to be independently assorted. This is true for most of the genes. But the linked genes are exception to this view.

Mendel studied genes present on different chromosome which was a lucky choice so he couldn't see linkage. "So one assumption is that the genes always are inherited independently and no linkage is there"

Mendel studied only recessive dominant type of inheritance while in nature the inheritance is more conplex. There is codominance , incomplete dominace , epistasis and various such interactions involving multiple genes.

"So second assumption for mendelian genetics to be true is that genes always have recessive dominant inheritance."

Mendle studies inclued only two alleles of a given trait. While we know multiple form of allels exist in nature (though only two would be present in an organism at a given time) like for ABO blood group.

"So third assumption is that there are only two allelic forms of a gene."

"Fourth assumption is one gene controls only a single trait". Which is not true as multiple effects of a gene are seen (called pleiotropy.)