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BHUTAN
Genetic analyses of population structure of Bhutanese
cattle reproduced by traditional cattle breeding systems
Tashi DORJI
BTN - 10801
Chief,
Ministry of Agriculture and Forests,
Diary Development Division, Department of Livestock
Japanese Advisor : Hideyuki MANNEN
Professor, Kobe University
The indigenous cattle are the
most important livestock genetic
resources for food, animal energy
and household income in Bhutan.
The native breeds have unique
disease resistance and adaptations
to the local environment and
provide basic raw material for breed
improvement for the Bhutanese
farmers. Nevertheless, increase in
Laboratory work with co-supervisor professor Yoshi
demand for domestic livestock Photo-1:
Kawamoto at the Laboratory of Primate Research Institute,
products favors crossbreeding of Inuyama, Kyoto University
low producing indigenous cattle
with the specialized exotic breeds.
As a consequence, the domestic
indigenous animal resources of
Bhutan are threatened by genetic
erosion. An effective management
of farm animal genetic resources
requires comprehensive knowledge
of the breed characteristics,
including molecular data on within
and between breed genetic diversity.
Field survey with principal Supervisor Professor
However, cattle populations in Bhutan Photo-2:
Hideyuki Mannen (Kobe University) at 4000m, AMSL , Paro,
are poorly characterized and Bhutan
described. Therefore, the objectives
of this study were to:
• Describe the traditional cattle breeding systems and their folk taxonomy and
• Understand the genetic constitution of cattle population using different
genetic tools (milk protein polymorphism, mtDNA, microsatellite markers)
and interpret its implications on native cattle conservation programme in
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Bhutan.
In this study, we have documented the rich folk nomenclatures that exist for
different bovines and its categories in Bhutan. Although, these terms continue to be
used today among farmers in rural communities throughout Bhutan, for the
younger generation, this knowledge is fast disappearing. The documentation of this
folk taxonomy provides better understanding of the less-known local breeds and in
preserving the precious branch of such indigenous knowledge for future reference.
Further, this study contributes to standardization of the use of folk terminologies
for cattle types and its categories in Bhutan. Specifically, we propose to use the
term Nublang-Thrabum (Nublang for male; Thrabum for female) for the indigenous
cattle breed of Bhutan. By using this term, we recognize the long tradition of
naming indigenous breeds, which has its own logical reasons that describe its
origin; Nub-meaning its origin from western Bhutan or Thra-diverse colour patterns
observed in Thrabum.
Livestock farming in Bhutan is typically related to low input subsistence
production systems and cattle herders inhabit marginal areas characterized by
extreme weather patterns of
unreliable rainfall or situated in the
high altitudes. As such, the traditional
breeding strategies have resulted in
animals that survive and reproduce
in hostile environments. This
indigenous animal breeding
knowledge, particularly involving
Mithun (Bos frontalis) and
Nublang-Thrabum provides a
repository of information for the
During field survey in Paro, Western Bhutan with
scientifically undocumented breeds Photo-3:
principal Supervisor Professor Hideyuki Mannen (Kobe
and traits. However, this traditional University)
Mithun-Thrabum hybridization has
never been verif ied by genomic
analysis. In this research, we
investigated milk protein variation
in cattle (Bos indicus), Mithun (Bos
frontalis), yak (Bos grunniens) and
their hybrid populations in Bhutan
to estimate genetic variability,
conduct genetic characterization
and assess the possibility of gene
During field survey in Zhemgang, central Bhutan with
flow between Mithun and cattle. Photo-4:
Co-Supervisor Professor Yoshi Kawamoto (Kyoto University)
Isoelectric focusing of 372 milk
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samples from 11 populations detected four molecular types of β-lactoglobulin (A,
B, E and M), five molecular types of αS1-casein (A, B, C, E and X) and three
molecular types of k-casein (A, B and X). Mithun and yak shared alleles but were
found to exhibit different allele frequencies for the proteins studied. The degree of
genetic variability within populations was measured by average heterozygosity and
ranged from 24–40% in cattle, 26% for yak and 33% for Mithun. Typically, the
detection of a Mithun specific molecular type M for β-lactoglobulin provided
useful tool to quantify Mithun genes into the village Thrabum populations. Also,
the variant αS1-CnX previously identified in the Nepalese and Dali cattle from
western Yunnan, China was found in the Bhutanese Thrabum and Indian Jaba but
absent in the Yak and Mithun populations. Similarly, k-CnX, a specific variant of
Yak occurred not only in Yak but also in Mithun with appreciable frequency.
Further investigation of these markers could provide useful tool to study the origin
and trace gene flow in the Asian cattle populations.
Furthermore, to determine genetic diversity and relationship of Bhutanese
indigenous cattle, we analyzed mtDNA D-loop sequence of cattle from three
populations of Bhutanese native cattle (Thrabum) and two Bhutanese populations
each of Tibetan (Goleng) and Indian (Jaba), and together with a Nepalese cattle
population. Although Bhutanese native cattle morphologically reveal them as Bos
indicus with the prominent hump, the three Thrabum populations included both
Bos indicus and Bos taurus types of mtDNA haplotypes. Almost all of Bhutanese
indigenous populations included both haplotypes assigned to either I1 or I2 clade
of Bos indicus with adequate frequencies, while Bos taurus type of haplogroups of
T1, T3 and/or T4 clades were observed in all the five Bhutanese indigenous
populations. The result indicated that indigenous cattle of Bhutan are admixture of
Bos taurus and Bos indicus, and that ancient taurine had contributed in the
formation of Bhutanese native cattle.
Although Mithun has been used in Bhutan for centuries, not much is known
about its origin and phylogeny. In order to characterize Mithun (Bos frontalis) and
increase our understanding of its origin, we sequenced the 16S rRNA gene in
mDNA. We compared Mithun with Yak, European cattle, Bhutanese zebu and
Indian zebu. Sequencing revealed low nucleotide diversity within the Mithun
population and their phylogenetic proximity to Gaur. A close relationship between
Bhutanese Mithun and Gaur was confirmed by an additional comparison with wild
Gaur specimens from three locations in Bhutan. Direct domestication of Mithun
from Gaur was supported, while maternal contribution from the cattle lineage
during domestication was not supported.
Likewise, we analyzed the genetic diversity and relationship of native
Nublang-Thrabum populations of Bhutan using 20 microsatellite markers. A total
of 120 Nublang-Thrabum cattle were sampled and were grouped according to their
geographical locations in four populations. Each included 30 individuals named
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Nublang-Thrabum West, Nublang-Thrabum South, Nublang-Thrabum Central and
Nublang-Thrabum East. Also, 30 samples of Indian Jaba (Bos indicus), Tibetan
Goleng (Bos taurus), Nepal Hill (Bos indicus), Holstein Friesian and Mithun (Bos
frontalis) were included. The mean number of alleles per loci (MNA) and observed
heterozygosity (Ho) were higher in the Nublang-Thrabum populations (MNA
7.2±0.3 – 8.9±0.5 and Ho 0.67±0.04 – 0.73±0.03) compared to Holstein Friesian
(MNA 5.8±0.5 and Ho 0.57±0.04). The smallest coeff icient of genetic
differentiation and genetic distance (FST 0.015 and DA 0.073) was obtained between
Nublang-Thrabum West and Central. The Nublang-Thrabum East was different
from other Nublang-Thrabum populations being closer to the Indian Jaba (FST 0.024
and DA 0.084). A high bootstrap value of 96% supported placement of NublangThrabum South, Nublang-Thrabum Central and Nublang-Thrabum West on the
same cluster.
In conclusion, the study contributed to better understanding of the traditional
breeding practices and genetic constitution of cattle genetic resources in Bhutan. In
particular, we have established that Bhutan has two Nublang-Thrabum populations
at the genetic level. Nublang-Thrabum West, South and Central are genetically
similar. The Nublang-Thrabum East is genetically apart from other NublangThrabum but closer to Jaba. We suggest that Nublang-Thrabum conservation
program in Bhutan should focus on the former population as it has received less
genetic influence from other cattle breeds. Future research is required to better
understand the origin of Mithun and develop genetic methods to evaluate its hybrid
populations. Additional information including data on population size and
structure, geographical distribution, their specific merits and socio-economic value
within the local context will facilitate effective management of animal genetic
resources in Bhutan.
Photo-5: During field survey in Zhemgang, central Bhutan with CoSupervisor Professor Yoshi Kawamoto (Kyoto University) and
professor Tetsyu Inamura (Aichi Prefecture University, Japan).
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