https://mmbr.asm.org/content/mmbr/46/1/1.full.pdf

Has the endosymbiont hypothesis been proven

A number of genes in higher organisms and in their viruses appear to be split. That is, they have "nonsense" stretches of DNA interspersed within the sense DNA. The cell produces a full RNA transcript of this DNA, nonsense and all, and then appears to splice out the nonsense sequences before sending the RNA to the cytoplasm. In this article what is known about these intervening sequences and about the processing of the RNA is outlined. Also discussed is their possible use and how they might have arisen in evolution.

https://science.sciencemag.org/content/sci/204/4390/264.full.pdf

Split Genes and RNA Splicing

The rabbit β-globin gene contains a large insert in the coding sequence

The ovalbumin gene is split in chicken DNA. Two interruptions in the sequences coding for ovalbumin mRNA have been detected, at least one of them lying in the protein coding sequence. The unexpected gene organisation is present both in oviduct cells highly specialised in ovalbumin synthesis and in erythrocytes.

Maria Pellegrini

Papers

Sequence arrangement of the rDNA of Drosophila melanogaster