Satellite DNA sequences have been studied in several groups of organis
ms, However, until now this type of sequence has not been characterize
d in cyclostomata, an evolutionarily important class of vertebrates, I
n the present work, we report the molecular characterization of a new
family of satellite DNA in lampreys (Petromyzon marinus). Digestion of
lamprey DNA with EcoRI identified a series of very abundant AT-rich (
60% A+T) repeating units, with short stretches of AT, that are multime
rs of 370 bp, Southern blot analysis and comparison with the satellite
DNA sequences deposited in the databases indicate that this new famil
y of satellite DNA is exclusive to lampreys. The distribution of this
EcoRI satellite DNA on lamprey chromosomes was analyzed by in situ hyb
ridization, The evolutionary origin of this satellite is briefly discu
ssed.