The mouse gene: ENSMUSG00000004500 has 2 human homologs: ENSG00000249471, and ENSG00000083812. Looking the opposite direction, the indicated mouse gene is the only mouse homolog of these two human genes. I was hoping someone from Ensembl could clarify why is this labeled "many2many" instead of "one2many"?
I retrieved a table of mouse homologs for human genes (Ensembl v104, data set Human Genes GRCh39) using the following biomart query:
Attribute set: "homologs radio button" Attributes:
- Homology related stats [ %identities, GOC, Alignment Coverage, and Confidence]
As I was reviewing the table, I found several records where the Mouse.homology.type was labeled "ortholog_many2many" where the homologous mouse gene had multiple human homologs, but those human homologs are only associated with the single mouse gene. Shouldn't these genes be labeled "one2many" as is true for most other similar cases:
R Filtering Code:
> with( + hom_2_mus %>% + select( + Human_ID=Gene.stable.ID, + Mouse_ID=Mouse.gene.stable.ID, + Mouse.homology.type + ) %>% + group_by(Human_ID) %>% + filter(n() == 1) %>% # Human genes with only one mouse homolog + group_by(Mouse_ID) %>% + filter(n() > 1), # Mouse genes with multiple human homologs + table(Mouse.homology.type) + ) Mouse.homology.type ortholog_many2many ortholog_one2many 44 1477