The inheritance rule was initially discovered by Mendel and it depends on clear

Question

The inheritance rule was initially discovered by Mendel and it depends on clear or qualitative traits. The theory was based on a single gene that was responsible for one character. However, expression of many traits are not governed by a single gene, rather can involve multiple genes as well as additive effects. This kind of inheritance pattern is known as quantitative (See cogbooks -> Genetic analysis of populations for more information) and is demonstrated by East (1916) as well as others. He performed experiments using 2 homozygous, pure-breeding lines of Nicotiana longiflorathat differed in corolla length. After crossing these lines, F1 offspring had an intermediate length for corolla and had same variation level as in parents. But found a very different result for F2 and F3 than expected. Discuss the reasons for this result and if it agrees/disagrees with Mendel’s law. Using obtained knowledge so far, what kind of cumulative effects would you add to this variation?

Here is a paper by East (1916):

https://myasucourses.asu.edu/bbcswebdav/pid-1611343-dt-forum-rid-124933901_1/courses/2018SummerA-X-BIO340-46443-44912/East_1916.pdf

Explanation / Answer

Edward east crossed homozygous parent of tobacco (nicotiana longiflora)

F1 generation had hardly any difference from parents though they were variable.

The F2 generation showed little variability, by selective breeding he created another generations F3… which had distinguish character in terms of height from original parent.

Findings were:

Polymorphism of locus may be responsible for the character of height.

Also there is environmental variation due to enviornmental factors in genetically similar plants that were used as parents.

Yes, Edward east agreed with Mendel that F2 progeny has more variability in character than F1 generation or progeny or the parent used in cross.

This happen due to recombination or segration / separation of gene during gamete formation (that was proposed by Mendel).

The cumulative effect can be polygenic inheritance.

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