In $Drosophila$,during organ differentiation,if one organ is transformed into another (e.g.,legs instead of wings),what is the gene responsible for such transformation called?

Read the following statements and identify the correct ones.
$(1)$ Linkage and recombination were first understood in $Lathyrus$ $odoratus$.
$(2)$ Mendel's work was rediscovered by Correns,Tschermak,and de Vries,which was published in $1900$.
$(3)$ $T.H.$ Morgan is considered the father of experimental genetics.
$(4)$ $A$ child born to parents with thalassemia major can be affected by thalassemia.
$(5)$ In birds,the female is homogametic and the male is heterogametic.

Example of intergenic gene interaction is/are

In order to determine whether variations of a character in a population were genetically controlled,the most appropriate procedure will be to

For obtaining a hybrid ratio,which characters of the plant are taken into account?

Which of the following phenomena leads to variation in $DNA$?