1. Intron Growth Insertions and Deletions of Introns in Human and Dog Sharndeep Kaur March 15, 2005 Bme 230

2. Topic- growth pattern The focus of my project was to determine the pattern of insertions/deletions of introns in human and dog over evolution. Did humans insert more introns over time or did dogs? Did humans lose more introns than dog?

3. Two-way alignment It was used to determine the insertions and deletions of introns. Human + Boreoeutherian Genome Dog + Boreoeutherian Genome Boreoeutheria ancestor is the most common ancestor because boreoeutheria are the largest clade, or group of species, of mammals.

4. Introns- background Discovered in 1977. Non-protein coding sequences of DNA that occur within functional genes. There are eight major classes of introns, each occurring in different locations. The most common introns in the genome of eukaryotes are the GU-AG introns (named for their splice sites).

5. Introns – cont. It’s surprising how little know about the origin and functions of introns. Introns are present in vast amount of numbers in our genome and we have yet to know it’s significance and origin. How do they spread in genes? What is the primary process by which new introns are created? How and why they get deleted or inserted?

6. It is hard to conclude the exact function of introns but because they have been carried over for a long time indicates that introns might carry some genetic significance because of their presence through out evolution.

7. Two hypotheses of intron evolution: “Intron early” The introns early theory states that introns were originated early in the genomic evolution process and are slowly being removed from eukaryotic genomes. “Intron late” The introns late theory states that introns are a recent development in the genome and are accumulating in rather than disappearing from eukaryotic genomes

8. Introns >100 bps The insertions and deletions are of introns that are greater than 100 base pairs. Deletions and insertions less than 100 base pairs were regarded as noise and were not used in the count of intron insertions and deletions for human and dog.

9. Counts of insertions/deletions Base PairsNumber of genes Human Insertions 73434924 Human Deletions 12181107 Dog Insertions 87573346 Dog Deletions 16291271

10. Conclusion As we can see there are more insertions than deletions in both human and dog. The dog genome is similar in size to the genomes of humans and other mammals, containing approximately 2.5 billion DNA base pairs. If we can figure out the correlation between the insertion and deletion patterns in both human and dog, we can further our knowledge about the functions, origin and significance of introns. Which can further our science in solving many unsolved mysteries of human genome.