Full Text Link httpswwwncbinlmnihgovpubmed824647 Title Hozum

Full Text Link: https://www.ncbi.nlm.nih.gov/pubmed/824647

Title: Hozumi &Tonegawa paper “Evidence for Somatic Rearrangement of Immunoglobulin Genes Coding for Variable and Constant Regions”

Questions:

1.  In the Discussion section of the paper, the authors assert that their data are consistent with the deletion model of DNA rearrangement, but not with the copy-insertion model. Explain, why.

Solution

Answer:

The authors assert that their data are consistent with the deletion model of DNA rearrangement, but not with the copy-insertion model.

In the \"copy-insertion\" model a specific V gene is duplicated and the copy is inserted at a site adjacent to a C gene. In this model, the embryonic sequence context of a V gene should be retained in the lymphocyte expressing that particular V gene. Since the embryonic DNA fragment carrying the MOPC 321 V gene does not seem to exist in the genome of this tumor, their results are clearly incompatible with this model.

In the \"deletion\" model, DNA in the interval between a particular V gene and the corresponding C gene loops out, is excised, and diluted out upon subsequent cell multiplication. It is the model along with other two models ( excision -insertion model and inversion model) consistent with the experimental results presented in this paper.