Homology help (#75)

* homology-table

* homology-table

* update-ref-arts

docs/ensembl-help/using-ensembl/ensembl-apps/entity-viewer/gene-homology.md

+---
+slug: gene-homology
+title: How to find homologous genes in the Entity viewer
+description: A table of the homologous genes found in other species for an individual gene of interest.
+---
+
+# How to find homologous genes in the Entity viewer
+
+Homologous genes share a common ancestor, being separated 'split' by a speciation event or a gene duplication event.
+
+A list of homologous genes for a given gene are found in the homology table. 
+
+The homology table for a gene is the first tab in the gene relationship panel found in the detailed view of a gene in the Entity viewer.
+
+<figure>
+  <img src="media/gene-homology.png" />
+  <figcaption>
+    A view of the homology table for BRCA2 in the Entity viewer.
+  </figcaption>
+</figure>
+
+For each gene homologue found in another species genome the following information is provided:
+
+* Common name: Domestic guinea pig
+* Scientific name: Cavia porcellus
+* % protein similarity: The percentage of identical amino acid residues aligned against each other.
+* % coverage: The percent of query which is in local alignment with the respective reference.
+* Gene symbol: Gene symbol for homologues in each species - these may vary between species .
+* Gene ID: the Ensembl ID - ENSG eg ENSCPOG00000005153.4.
+* Hit type: The type of homology: RBBH: reciprocal best blast hit, BBH: best blast hit.
+* Assembly: Genome assembly.
+
+### Customising the table
+
+You can reorder the table by sorting on a specific column. To sort the content of a column click on the arrow next to the column heading. 
+
+Sorting a specific column will in turn reorganise the information in all other columns of the table.
+
+You can also customise the table by hiding unwanted rows and columns by selecting the appropriate option in the Action dropdown at the top left of the homology table.
+
+You can download both a customised or uncustomised version of the table selecting the download option in the Action dropdown.
+