The study revealed unique genetic characteristics observed in the marmoset, including several genes that are likely responsible for their ability to consistently reproduce multiple births.
"Unlike humans, marmosets consistently give birth to twins without the association of any medical issues," said Worley. "So why is it OK in marmosets but not in humans where it is considered high risk and associated with more complications?"
It turns out the marmoset gene WFIKKN1 exhibits changes associated with twinning in marmosets.
"From our analysis it appears that the gene may act as some kind of critical switch between multiples and singleton pregnancies, though it is not the only gene involved," said Rogers, who added the finding could apply to studies of multiple pregnancies in humans.
The team was also looked for genetic changes associated with a unique trait found in marmosets and their close relatives, but not described in any other mammal. The dizygotic (or fraternal) twins in marmosets exchange blood stem cells called hematopoietic stem cells in utero, which leads to chimerism, a single organism composed of genetically distinct cells.
"This is very unusual. The twins are full siblings, but if you draw a blood sample from one animal, between 10 and 50 percent of the cells will carry the sibling's DNA," said Rogers. "Normally, fraternal twins do not share the same DNA in this way, and in other animals, this chimerism can cause medical problems but not in marmosets. It is very unique."
|Contact: Glenna Picton|
Baylor College of Medicine