phy:SequenceRelationType

<xs:simpleType name="SequenceRelationType">
  <xs:restriction base="xs:token">
    <xs:enumeration value="orthology"/>
    <xs:enumeration value="one_to_one_orthology"/>
    <xs:enumeration value="super_orthology"/>
    <xs:enumeration value="paralogy"/>
    <xs:enumeration value="ultra_paralogy"/>
    <xs:enumeration value="xenology"/>
    <xs:enumeration value="unknown"/>
    <xs:enumeration value="other"/>
  </xs:restriction>
</xs:simpleType>