A review of basic
genetics
Chromosomes
Chromosomes
Chromosomes
Chromatid
Centromere
Chromatid
Chromosomes
Different species differs in
Shape
Size
Number
Within any species
Occurs in pairs
Chromosomes
Chromosome pair have same shape and size
in individual of one sex
In other sex, two chromosomes that
remained as unequal pair differ in shape and
size
This difference is the key to sex
determination
Chromosomes
Two unequal chromosomes occurs in male
and are called X and Y whereas females
consists of two X chromosomes.
XY is male and XX is female in mammals
X and Y chromosomes are called sex
chromosomes while rest are called
autosomes
Chromosomes
However in birds, sex chromosomes are
given different names
ZZ is male and ZW is female
Chromosomes
Sex chromosomes + autosomes = genome (
total set in cell)
Genomes are said to be diploid (2n)
On the basis of centromere location,
chromosomes are:
Acrocentric
Metacentric
Sub-metacentric
Find out chromosomes in
following species
Yak
Buffalo
Siri
Mithun
Mule
Ass
Duck
References for assignment
Dorji, T. et al. (2002). Genetic diversity in Bhutanese yak (Bos grunniens) populations
using microsatellite markers. Proceedings of the third international congress on yak, in
Lhasa, China, 4-9 September 2000. International Livestock Research Institute (ILRI),
Nairobi, pp. 197-201.
Gupta, N. et al. (1996). Chromosomes of yak. Indian Journal of Animal Sciences, 66:
453-457.
Vijh, R.K., M.S. Tanita and R. Sahai. 1994. Translocation in Murrah buffalo. Indian J.
Anim. Sci., 64: 534-538
Winter H, et al. 1986. Genetic characterisation of the mithun (Bos frontalis) and studies of
spermatogenesis, blood groups and haemoglobins of its hybrids with Bos indicus.
Res Vet Sci. 8-17.
José M. Trujillo et al. 1962. Chromosomes of the horse, the donkey, and the mule.
Chromosoma Volume 13, Number 3, 243-248