It has been well established that vertebrates have four hox clusters
as opposed to all other sub-phyla of animals which have one. I`ve
been trying to determine the number of Hox clusters in Agnathans.
I`m not sure if it has been shown that Agnathans have four, two,
or one cluster. This could have important evolutionary and developmental
implications if the number of clusters is different from all other
vertebrate classes. If anyone has information regarding this question
I would be most greatful for a reply. Thanks