Find a eukaryotic homolog of a prokaryotic gene:
mutL homolog in the Drosophila genome

Earlier we saw that there appeared to be mutL homologues in eukaryotic Genomes such as that of the Human (known as MLH1 in Human). Find the equivalent of the prokaryotic mutL gene in Drosophila...

There are several ways of doing this:

• By Gene Name:
  • From the the Genomic Biology Page, go to the Fruit Fly (Drosphila) Map Viewer and run a search for MLH1 (in earlier exercises in this course, we saw that MLH1 was the name used in higher organisms for MutL) in the Drosophila Genome (FIGS 7A-B).
  • See the resulting "hit" on chromosome 2R for "Mlh1"
  • Select the "gene seq" map from that page
  • See the resulting MutL like gene on the Map VIewer
• By BLASTing the Haemophilus influenzae mutL protein sequence (why protein instead of nucleotide?) against the Honey Bee genome:
  • Retrieve the amino acid sequence of the mutL protein from the Haemophilus influenzae Genome in FASTA format as per earlier exercise
  • Copy the FASTA sequence and paste it into “BLAST Drosophila melanogaster Sequences” site, which is accessed via the BLAST link on the Genomic Biology Page at http://www.ncbi.nlm.nih.gov/Genomes/, and run a blastp search against the RefSeq Protein dataset and BlastP (see FIGS 7C-D)
  • Note the resulting high E-Value BLAST hit—"ref|NP_477022.1| Mlh1 CG11482-PA [Drosophila melanogaster]"

FIG 7A: Result on MAP VIEWER SUMMARY PAGE for MLH1 search

FIG 7B: Map View of mutL homologue (MLH1) in Drosophila

FIG 7C: BLAST the Drosophila genome with the Haemophilous influenzae mutL protein sequence

FIG 7D: Result of BLAST the Drosophila genome with the Haemophilous influenzae mutL protein sequence