Question

Steve independently transformed lentil with either the pea Rms3 or the Rms4 genes, both of which are candidates for increasing lentil leaf size. Describe how he should first test his transgenic lines and then how he should intercross and select for plants that were homozygous for both Rms3 and Rms4.

Answer 1

In such a case when phenotype is same then we should check the gentotype. Using restriction mapping technique we can determine the changes in DNA sequences i.e. DNA finger pirnting. It is just like finger print of human i.e. unique. In this study a specified restriction endonuclease is selected for digestion of different samples giving different sizes separated in agarose gel electrophoresis. The separated DNA bands were visualized by randomly selected single stranded oligonucletide sequence radiolabelled. It should give random visualization of bands generally unique for unique sequence if matches then change the restriction enzyme or sequence of radiolabelled probe. At second or third change it must be unique.

So here in this case when Rms 3 and Rms 4 gene are transformed we can compare the DNA ladder of non transformed with transformed DNA sequence these must be different. Also Rms 3 and Rms 4 are different from each other unique bands can be identified

In second situation when the homozygous for both is to be selected. DNA ladder of such individual should match unique bands with both of Rms 3 and Rms 4