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HomoloGene Ddatabase

6. Search the OMIM database for “BRCA1” and click on the entry, “*113705.BREAST CANCER 1 GENE; BRCA1.” What does BRCA1 play critical roles in?

7. Check another database to see what information it has about BRCA1. Go to to search the NCBI database of genes.

8. Type in “BRCA1” in the search box to find entries of this gene among organisms with genetic information stored within NCBI’s database.

9. At the top of the list, click on the “BRCA1” link (ID 672) under “Name/Gene ID” at the top of the list.  This will take you to the database entry for human BRCA1.

10. Read the “Summary” section to get a brief synopsis of the functions played by human BRCA1 proteins.

11. Did NCBI's Gene database give you information about the function of the protein product of the gene BRCA1 that you also discovered in the OMIM database? List any additional descriptions from NCBI's Gene database that helped you understand the function of the BRCA1 protein.

12. Based on what you've learned about the BRCA1 protein, create a hypothesis for what happens when BRCA1 is mutated and malfunctions. Fill in the blank with a statement that could be tested, “A BRCA1 mutation causes ____________.”

The functions of BRCA1 sound important for cells other than breast cells and potentially for animals other than humans. The HomoloGene database allows you to see what species share genes that are thought to be “homologs.” A homolog is a gene that is similar in structure and evolutionary origin to a gene in another species.

13. Enter this HomoloGene URL into your browser. You will see a page entitled, "HomoloGene:5276. Gene conserved in Amniota," which lists other species that have a version of the BRCA1 protein. This list is on the left, with humans (“BRCA1, H. sapiens”) at the top. List the scientific name and the common name of the nonhuman species that have a version of a BRCA1 protein. Why might the BRCA1 protein be found in other animals?

On the right of the HomoloGene BRCA1webpage, you can see what key parts of the protein are the same for each species (listed under “Proteins”). Each species’ protein is color-coded for the functioning parts that are also found in the other species’ BRCA1 proteins. These key regions of the protein are listed and described technically in the “Conserved Domains” section of this webpage. All identified proteins have a specific number, called an “accession number” that starts with a prefix such as “NP_,” which lets researchers know it is a protein rather than another type of molecule. Human BRCA1 protein has the number NP_009231.

Additional Resources

More about "conserved sequences"