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End date: 2006 × Start date: 2006 × Thesis Type: Ph.D ×
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    ThesisItemOpen Access
    PRENATAL DEVELOPMENT OF THE BUFFALO SKULL (Bubalus bubalis)
    (SRI VENKATESWARA VETERINARY UNIVERSITY TIRUPATI - 517 502. (A.P.) INDIA, 2006-10) SANTHI LAKSHMI, M; Chandrasekhara Rao, T.S(MAJOR); Pramod Kumar, D; Raghavender, K.B.P; Girish Kumar, V
    ABSTRACT : The present work was undertaken on 509 embryos and fetuses of Buffalo belonging to 112 age groups starting from 26 d to 310 d to study the prenatal development of facial and cranial bones and also the relationship of the developing skull with other structures of the head at different stages. Developmentally the bones of the buffalo skull were divisible into four groups i.e. Cartilaginous neurocranium, Membranous neurocranium, Membranous viscerocranium and Cartilaginous viscerocranium. The bones of the chondrocranium consisted of lower part of squamous occipital, exoccipital, basioccipital, petrous temporal, tympanic bulla, basisphenoid, presphenoid, ethmoid and turbinates. The frontal, parietal, interparietal and upper part of squamous occipital formed the desmocranium. The premaxilla, maxilla, palatine, pterygoid except its hamulus, malar, squamous temporal, tympanic ring, lacrimal, nasal, vomer and mandible except its condyle constituted membranous viscerocranium. The Meckel’s cartilage and its derivatives malleus and incus, mandibular condyle, Reichert’s cartilage and its derivatives including stapes, tympanohyoid, hyoid, styloid process of temporal and hamulus pterygoideus formed the cartilaginous viscerocranium. The chondrocranium was divisible into basal plate, prechordal part and paired otic and nasal capsules around sensory epithelia. The basal plate cartilage formed the basioccipital, exoccipital and lower part of the squamous occipital. The otic capsule formed petrous temporal bone and tympanic bulla. The prechordal part formed basisphenoid caudally and presphenoid cranially. The nasal capsule formed the ethmoid, turbinates, nasal septum and nasal cartilages. The bones of the cartilaginous neurocranium and cartilaginous viscerocranium were formed by endochondral ossification while intramembranous bone formation was seen in the bones of the membranous neurocranium and membranous viscerocranium. The bones of floor of the cranium except basioccipital were ossified from multiple centers. Most of the facial bones except mandible, vomer and hyoid as well as calvarial bones were ossified from single centers. Most of the chondrocranium was cartilaginous at 45 d. The ossification of skull first appeared in mandible, maxilla and malar at 45 d. Early ossification of lacrimal, squamous temporal and tympanic ring was evident at 49 d. The ossification of palatine was first observed at 53 d while premaxilla and vomer showed ossification at 56 d. The ossification of nasal bone was observed at 61 d. The ossification of desmocranium first appeared in frontal at 49 d. Parietal and interparietal bones showed ossification at 60 d and 64 d respectively. The ossification of chondrocranium first appeared in occipital and sphenoid at 62 d. The last bone of the skull to ossify was the dorsal turbinate. The maxillary sinus appeared first at 92 d among the sinuses of the skull. Five fontanelles in total i.e. unpaired anterior fontanelle, paired mastoid and sphenoidal fontanelles were observed. Wormian bones were observed at frontonasal junction in a few cases. The craniofacial index of skulls of 98 d to 310 d was ranged from 4.3: 1.8 to 13.7:13.5. The otic and optic vesicles were evident at 26 d. The enamel organs of premolars of upper jaw and incisors and premolars of lower jaw were evident at 62 d. The formation of choroid plexuses of ventricles was evident at 43 d while development of pituitary was observed at 41 d.
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    ThesisItemOpen Access
    ASSESSMENT OF GENETIC DIVERSITY IN CHICKEN POPULATIONS USING GENOME MARKERS
    (SRI VENKATESWARA VETERINARY UNIVERSITY TIRUPATI - 517 502. (A.P.) INDIA, 2006-06) RAJKUMAR, ULLENGALA; NIYAL AHMED, (MAJOR); SHEKHAR, C. MANDE; VENKTRAMAIAH, A; RAJASHEKHAR REDDY, A
    ABSTRACT: A total of 155 birds representing eight populations, two layer strains of White Leghorn (WLH-IWD and WLH-IWF). two dual-purpose breeds (Dahlem Red and Rhode Island Red), a commercial layer (Babcock), a commercial broiler (Vencobb), a native breed (Aseel) and Non-descript (Desi) chicken were genotyped with twenty (mono, di and tri nucleotide repeats) microsatellite markers to assess the genetic diversity, genetic variation and phylogenetic relationships. All the microsatellite loci utilized for the analysis were polymorphic with a reasonable informativeness ranging from moderate to high. The total number of alleles obtained across all the populations was 285 with a size range from 76 for MCWO51 to 256 for MCWOOS locus. The total number of alleles per locus ranged from 7 at MCW001 to 26 at MCWOOS with an overall mean of 14.25 alleles per locus. The mean number of alleles across the loci and among the populations ranged from 3.50 (ADL158) to 8.63 (ADL176 and MCWOOS) and 4.70 (WLH-IWD) to 6.75 (Non-descript). The mean effective number of alleles am-ng the loci and the populations varied between 1.96 for ADL158 and 4.4 1 for ADL267 and 2.69 in Dahlem Red and 4.15 in Non-descript. A total of 103 alleles were unique to population/strain in various chicken populations. The frequency of most of these alleles was very less. Only 30 per cent of the alleles had frequency of more than 10 per cent. The mean Polymorphism Information Content (PIC) values ranged from 0.39 for ADL158 to 0.71 for MCWOOS and ADL267 across the loci and 0.55 (Dahlem Red) to 0.71 (Non-descript) among the populations. The expected heterozygosity estimates ranged from 0.63 (Dahlem Red) to 0.77 (Non-descript) with an overall mean of 0.68. The observed heterozygosity estimates were the highest in Babcock (0.73) and the least in Dahlem Red (0.55) among the populations studied. The overall mean inbreeding coefficients (FIs) varied between -0.05 (Babcock) and 0.16 (Rhode lsland Red). Babcock, a commercial layer had negative Fls value (-0.05) indicating high genetic variation and outbreeding effects. The genetic distance was least between WLH-IWD and WLH-IWF (0.30) and highest between Dahlem Red and Babcock (0.80). The WLH-IWD and WLH-IWF strains were closer with maximum genetic identity index of 0.75 among all the populations and Dahlem Red and Babcock were wider apart with least identity index value of 0.45 indicating their high genetic divergence. Phylogenetic analysis revealed that the eight populations were grouped in to two main clusters, one cluster representing Dahlem Red and Rhode Island Red, the pure breeds and the other cluster representing the remaining six populations/strains (two commercial, two synthetic strains and two native chickens). The second group was divided into three sub clusters i.e., Aseel and Non-descript; Babcock and Vencobb; WLH-IWD and WLH-IWF. All the loci departed from the equilibrium frequency in at least two of the eight populations studied. It may be concluded that the chicken populations studied were in the state of mild to moderate inbreeding except commercial birds. A planned breeding is suggested for purebreds to revive their genetic potential. High genetic diversity exists in Non-descript birds, which can be tapped to improve the birds suitable for backyard poultry.