9) Trophoblast external to barrier
There is no infiltration of trophoblast.
10) Endometrium
There are no reports and I have not had a uterus available for study.
11) Various features
None.
12) Endocrinology
No studies have been published to provide endocrine data. The animals have a birth interval of about one year.
13) Genetics
Takins have 52 chromosomes, while the muskox has 48. Both have the same NF (fundamental number) that suggested a closer relationship to us (Bogart & Benirschke, 1975; Pasitschniak-Arts et al., 1994). The latter authors performed an extensive study of takin, muskox and sheep chromosomes. In addition, they reviewed the sparse and conflicting anatomic literature of these species without firmly resolving the controversial aspects. Another point of view of the relation of takin to muskox was expressed by Groves & Shields (1997). These investigators studied the cytochrome-b mtDNA gene of these animals, and of three caprine species, to test the possibility of a common ancestor for muskox and takin. They rejected this hypothesis and suggested that convergent evolution was more likely to give rise to the similar phenotypes (size, horns, hair) and behavior of takin and muskox. Many additional cytogenetic studies have since been performed by us and these show a uniform 2n=52 for both subspecies. Hybrids have not been described.
14) Immunology
I know of no studies.
15) Pathological features
No reports are available on pathologic features.
16) Physiologic data
No data are available.
17) Other resources
The CRES facility of the Zoological Society of San Diego has cell strains of both Mishmi and Sichuan takins. Both subspecies exist in sizeable breeding groups at the San Diego Zoo. These can be obtained by contacting Dr. Oliver Ryder at: oryder@ucsd.edu.
18) What additional information is needed?
Better preservation (more rapid fixation) of new placentas is imperative.
Acknowledgement
Most of the animal photographs in these chapters come from the Zoological Society of San Diego. I appreciate also very much the help of the pathologists at the San Diego Zoo.
References
Aung, H.: A note on the birth of a Mishmi takin Budorcas t. taxicolor at Ragoon zoo. Intern. Zoo Yearb. 8:145, 1968.
Bogart, M. and Benirschke, K.: Chromosomes of a male takin, (Budorcas taxicolor taxicolor). Chromos. Inf. Serv. 16:18-20, 1975.
Gotch, A.F.: Mammals - Their Latin Names Explained. Blandford Press, Poole, Dorset, 1979.
Groves, P. and Shields, G.F.: Cytochrome B sequences suggest convergent evolution of the Asian takin and Arctic muskox. Mol. Phylogenet. Evol. 8:363-374, 1997.
Nowak, R.M.: Walker's Mammals of the World. 6th ed. The Johns Hopkins Press, Baltimore, 1999.
Pasitschniak-Arts, M., Flood, P.F., Schmutz, S.M. and Seidel, B.: A comparison of G-band patterns of the muskox and takin and their evolutionary relationship to sheep. J. Hered. 85:143-147, 1994.
Penny, C.: Sichuan takin calves born at the San Diego Zoo. Amer. Ass. Zool. Parks Aquar. Newsl. 30:17, 1989.
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