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1984 - 19882
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Subject: Animal Genetics and Breeding × Author: KAU × End date: 1989 × Start date: 1984 × Thesis Type: M.V.Sc. ×
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    ThesisItemOpen Access
    Chromosome profile of Indian elephants ( Elephas maximus indicus)
    (Department of Animal Breeding and Genetics, College of Veterinary and Animal Sciences, Mannuthy, 1988) Sakthi Kumar, A; KAU; Mukundan, G
    A karyological study in Indian elephants using peripheral venous blood collected from 7 tuskers, 7 cow elephants and one makhna belonging to some temples and private owners of Trichur District was undertaken with objectives of a) to evolve a technique for chromosome studies of elephants. b) to find out the chromosome number in Indian elephants, and c) to suggest sex chromosome mechanism in sex determination. Standardization of technique Comparison of efficacy of phytohaemagglutinin – M (Difco) and Poke – weed mitogen (GIBCO), in two different culture media namely TC 199 and RPMI – 1640, as mitogens showed that phyto – haemagglutinin – M yielded a mitotic index of 0.33 and 0.66 per cent in medium TC 199 and RPMI – 1640 respectively; poke – weed mitogen yielded a mitotic index of 5.33 and 5.66 per cent respectively in TC 199 and RPMI – 1640. Statistical analysis revealed that the efficacy of the two different media used was not significantly different, whereas the efficacy of two mitogens differed significantly at five per cent level. Poke – weed mitogen was found to be better than phytohaemagglutinin – M as far as indusing mitoses in elephant lymphocyte cultures over a 72 hour culture period was concerned. Colchicine treatment using 0.1 ml colchicine solution (0.0001%) for a period of one hour yielded satisfactory chromosome preparations. Karyotype The karyotype of the tusker, cow elephant and makhna revealed a diploid chromosome number of 2n = 56, comprising of 54 autosomes and 2 sex chromosomes. The autosomes were classified into 6 submetacentric and 21 acrocentric chromosomes. The X – chromosome was a submetacentric in all the three groups of elephants whereas the Y – chromosome was a small acrocentric in the tusker as well as the makhna. Analysis of relative length of chromosomes showed that the largest chromosome pair measured a relative length of 6.973 per cent and the smallest chromosome was the Y – chromosome measuring a relative length of 1.710 per cent. Position of centromere on the basis of centromeric index suggested that the centromere was farthest from the centre of the chromosome in the second autosome pair and nearest to the centre in the X – chromosome among the submetacentric chromosomes. Neither autosomes nor sex chromosomes possessed satellites on karyological examination. The elephants studied exhibited XX/XY sex chromosome mechanism. The cow elephant possessed XX sex chromosome complement while both tusker and makhna possessed XY sex chromosome complement. A comparison between the karyotypes of tusker and makhna did not show any variation in (a) basic number, (b) relative length (C) position of centromere, (d) absence of satellites on the chromosomes and (e) the sex chromosome complement. It may be concluded that tusklessness in makhna is not associated with either euploidy or aneuploidy.
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    ThesisItemOpen Access
    Genetic studies on polymorphism of some blood proteins in goats
    (Department of Animal Breeding and Genetics, College of Veterinary and Animal Sciences, Mannuthy, 1984) Shamsuddin, A K; KAU; Mukundan, G
    Blood samples collected from goats maintained in the farm under All India coordinated Research Project on Goats for Milk of Kerala Agricultural University, Mannuthy, formed the materials for this study. These blood samples were typed employing horizontal starch – gel – electrophoresis to study the polymorphism of haemoglobin, transferrin, albumin and amylase. In all 188 goats comprising 40 Malabari, 72 Saanen x Malabari (halfbred) and 76 Alpine x Malabari (halfbred) were involved in the study. Inter and intra population variability was studied. Genetic interrelationship among some growth, production and reproduction traits viz. body weights at birth, 3 months, 6 months and 12 months, age at first kidding, first lactation yield (120 days), peak yield and interkidding interval was determined. Two haemoglobin variants, the faster HbA and slower HbB with two phenotypes HbAA and HbAB were observed. The gene frequency of HbA in Malabari, Saanen halfbred and Alpine halfbred goats was 0.9750, 0.9792 and 0. 9671 respectively and that of HbB in these three genetic groups was 0.0250, 0.0208 and 0.0329 respectively. The frequency of HbA allele was higher in all the populations. Four transferrin phenotypes TfAA, TfAB, TfBB and TfAC controlled by three co – dominant alleles TfA , TfB and TfC were observed. The fast moving variant was designated as TfA followed by TfB and TfC. In Malabari goats TfAC was not observed. The frequency of TfAB type was higher in all the genetic groups. The gene frequencies of TfA, TfB and TfC in Malabari goats were 0.4500, 0.5500 and zero respectively. TfC allele was not observed in Malabari goats. Three Tf alleles namely TfA, TfB and TfC were revealed in the crossbred populations with a preponderance of TfA allele. The frequencies of TfA, TfB and TfC alleles in Saanen halfbreds were 0.5278, 0.4236 and 0. 0486 and in Alpine halfbreds were 0.5329, 0.4539 and 0.0132 respectively. The allelic frequencies of haemoglobin and transferrinloci were suggestive of Hardy – Weinberg equilibrium in all the three population or goats. Magnitude of inter population variability among the three genetic groups was negligible. The autosomal co – dominant mode of inheritance for Tf alleles was demonstrated by analysis of segregation patterns observed in pedigrees. Significant association was observed between the TfAA phenotype and economic traits such as birth weight, first lactation yield and peak yield. Polymorphism was not observed for the albumin and amylase systems. Maximum heterozygosity was observed at the transferrin locus. Highest average heterozygosity was exhibited by the Saanen halfbred goats. Among the four biochemical of blood studied, transferrin reflected a great scope for serving as a genetic marker to be used in selection of goats for improved milk production.