Corinna Ross M.A. 1999 University of Nebraska-Omaha B.S. 1997 Cornell University Ph.D. 2005 University of Nebraska-Lincoln Postdoctoral Fellow University of Texas Health Science Center Barshop Institute for Longevity & Aging Studies STCBM Building Suite 3.325 15355 Lambda Drive San Antonio, TX 78245-3207 office: (210) 562-6012 fax: (210) 562-5093 Email: rossc4@uthscsa.edu

Genetic chimaerism in marmosets (Callithrix kuhlii)

Studies of population genetics, cooperative breeding behavior, and paternity in primates are based on several assumptions about heredity that are not true for marmosets and tamarins (family Callitrichidae). Callitrichids have unique social and biological reproductive strategies, one of which is obligate fraternal twinning. During early development, the blastocysts of the fraternal twins fuse, forming a single chorion. Later development of multiple vascular anastomoses in the placenta allows the exchange of stem cells, causing the twins to develop as genetic chimeras. Although the consequences of such events have been discussed in the literature, to date no study has thoroughly examined the extent and tissue distribution of chimerism in marmosets. It is not clear whether this phenomenon affects somatic tissues only, or if it may also involve the germline. Documenting the extent and distribution of genetic chimerism will increase our understanding of putative evolutionary consequences, such as development of cooperative breeding and paternal care among callitrichids and, more generally, of intergenomic conflicts. This research will address the following goals: a) characterize the marmoset model system using tissue samples available from the breeding colony at the University of Nebraska, b) develop microsatellite markers for this system, c) assess the extent and distribution of chimerism between fraternal twins, and d) evaluate genetic paternity in polyandrous social groups.

(Black Dog is from the University of Notre Dame student newspaper's comics section)

PUBLICATIONS:

-Ross, C., J. French, and G. Ortí. 2007. Germ Line Chimerism and Paternal Care in Marmosets (Callithrix kuhlii). Proc. Natl. Acad. Sci. USA, 104 (15): 6278–6282.

- Fite, J.E., Patera, K.J., French, J.A., Rukstalis, M., Hopkins, E.C., Ross, C.N.(2005). Opportunistic mothers: female marmosets (Callithrix kuhlii) reduce their investment in offspring when they have to, and when theycan. Journal of Human Evolution, 49: 122-142.

- Fite, J. E., French, J. A., Patera, K. J., Hopkins, E. C., Rukstalis, M., & Ross, C. N. (2005). Elevated urinary testosterone excretion and decreased maternal caregiving effort in marmosets when conception occurs during the period of infant dependence. Hormones and Behavior, 47: 39-48.

- Ross, C.N., French, J.A., and Patera, K. (2004). Intensity of aggressive interactions modulates testosterone in male marmosets. Physiology and Behavior, 83: 437-445.

- Fite, J.E., French, J.A., Patera, K., Hopkins, E., Rukstalis, M., Jensen, H., and Ross, C.N. (2003). Nighttime wakefulness associated with infant rearing in Callithrix kuhlii. International Journal of Primatology, 24(6): 1267-1280.