The significance of the G-bands and C-bands of three different Robertsonian translocations of domestic sheep (Ovis aries)

1974 ◽  
Vol 13 (5) ◽  
pp. 479-488 ◽  
Author(s):  
A.N. Bruère ◽  
D.L. Zartman ◽  
H.M. Chapman
Genome ◽  
1994 ◽  
Vol 37 (4) ◽  
pp. 672-678 ◽  
Author(s):  
K. Dai ◽  
A. E. Dollin ◽  
C. B. Gillies

Meiotic chromosome pairing behaviour in three normal sheep was surveyed by synaptonemal complex (SC) analysis at the electron microscope level. The SC karyotype of normal rams is composed of a sex pair, three metacentric or submetacentric pairs, and 23 acrocentric autosomal bivalents, with the total autosomal SC length ranging from 309 to 315 μm. Five nucleoli are terminally located on the three metacentric, and one large and one small acrocentric autosomal bivalents. XY morphology was used to divide pachytene into five substages. Although pairing abnormalities (mostly SC interactions) were recorded in an average of 16% of the spermatocytes, bivalent–XY association occurred in only 4.7% of the cells.Key words: sheep, synaptonemal complex, XY pair, pachytene substaging.


Genome ◽  
1994 ◽  
Vol 37 (4) ◽  
pp. 679-689 ◽  
Author(s):  
K. Dai ◽  
C. B. Gillies ◽  
A. E. Dollin

Zygotene and pachytene spermatocytes from Massey I (t1 5;26) and Massey II (t2 8;11) translocation heterozygotes each contained one trivalent, often delayed in pairing, while cells from double Massey translocation heterozygotes had two such trivalents. As meiosis progressed, trivalents became fully paired, with acrocentric axes in a cis configuration. Abnormal pairing configurations often resulted from interactions between unpaired chromosome axes or segments. However, when two Massey trivalents were present in the same nucleus, there was no pairing interaction between them. In different Massey translocation heterozygotes, trivalent-involved pairing abnormalities occurred in 14–28% of cells, with XY–trivalent and XY–bivalent–trivalent associations being as high as 7.1–23.1%. In spermatocytes from single and double Massey translocation heterozygotes with normal-sized testes, the total SC abnormality frequency was 34.4% for the t1 heterozygotes, 27.1% for the t2 heterozygotes, and 21.4% for the double heterozygote. One Massey II heterozygote with one normal and one small testis had significantly higher SC abnormality frequency (54%) than normal rams. A trisomic cell was recorded in one ram and two hyperdiploid cells in another ram, but these were unrelated to the translocations. It is suggested that resolution of pairing abnormalities by synaptic adjustment is important in reducing the effects on fertility of the translocations.Key words: sheep, Robertsonian translocation, trivalent, abnormal pairing configuration.


Genome ◽  
1994 ◽  
Vol 37 (5) ◽  
pp. 802-808 ◽  
Author(s):  
K. Dai ◽  
C. B. Gillies ◽  
A. E. Dollin

Spermatocytes from rams heterozygous for Massey translocation III (t37;25) contained one trivalent and those from the rams heterozygous for both Massey translocations I and III (t1t3) contained two trivalents. Where two trivalents and the XY pair are present in the same nucleus they may form a synaptonemal complex (SC), but no SC segment is found between the two trivalents. The frequency of pairing abnormality in four t3 rams and two t1t3 rams did not significantly differ from that in the normal sheep, but t3 trivalents with diverse abnormal configurations were recorded. A hypothesis was proposed that nucleolar organizer regions (NORs) or nucleoli could account for deficient pairing behaviour and hence chromosome rearrangement, because the NOR region on an NOR-bearing chromosome was usually delayed in pairing, and unpaired regions tended to associate with other unpaired axes or SCs.Key words: Bovidae, NOR, deficient pairing, chromosome rearrangement.


Author(s):  
Hussein Migdadi ◽  
Nizar Haddad ◽  
Ruba AlOmari ◽  
Mohammad Brake ◽  
Mustafa AlShdaifat ◽  
...  

Background: Jordanian Awassi sheep (Ovis aries) is the dominant fat tail sheep breed that appeals to customers because of its various production systems, including fiber, meat and milk. This report is the first whole ewe genome sequence (WGS) of O. aries submitted in the NCBI database from Jordan. Methods: 64 Paired-end sequencing libraries were constructed and subjected to Illumina Hiseq 2500 sequencing system. High-quality reads were aligned against the reference sheep genome and detecting comprehensive sources (SNPs, InDels, SV, CNVs) of genetic variations. We have deposited data sequences at the NCBI under SRA (sequence reads archives) under the accession numbers SRR11128863, PRJNA574879. Result: Genome resequencing of Jordanian Awassi ewe was carried out with approximately 93.88 Gb with a mapping rate and effective mapping depths were 99.28% and 36.32. Around 19 million SNPs, 3,6 million InDels, 35,180 Structure variation and 13,524 copy number variation among the Jordanian ewe genome were detected. This wide range of genetic variation provides a framework for further genetic studies that will help understand the molecular basis underlying phenotypic variation of economically important traits in sheep and improve intrinsic defects in domestic sheep breeds.


2009 ◽  
Vol 57 (1) ◽  
pp. 23 ◽  
Author(s):  
A. J. Munn ◽  
T. J. Dawson ◽  
S. R. McLeod ◽  
D. B. Croft ◽  
M. B. Thompson ◽  
...  

Sustainable management of pastures requires detailed knowledge of total grazing pressure, but this information is critically lacking in Australia’s rangelands where livestock co-occur with large herbivorous marsupials. We present the first comparative measure of the field metabolic rate (an index of food requirement) of Australia’s largest marsupial, the red kangaroo (Macropus rufus), with that of domestic sheep (Ovis aries; merino breed). We tested the assumption that the grazing pressure of red kangaroos is equivalent to 0.7 sheep, and show this to be a two-fold overestimation of their contribution to total grazing. Moreover, kangaroos had extraordinarily lower rates of water turnover, being only 13% that of sheep. Consequently, our data support arguments that the removal of kangaroos may not markedly improve rangeland capacity for domestic stock. Furthermore, given the low resource requirements of kangaroos, their use in consumptive and non-consumptive enterprises can provide additional benefits for Australia’s rangelands than may occur under traditional rangeland practices.


Zootaxa ◽  
2017 ◽  
Vol 4258 (6) ◽  
pp. 581 ◽  
Author(s):  
FRANCIANE CEDROLA ◽  
ROBERTO JÚNIO PEDROSO DIAS ◽  
ISABEL MARTINELE ◽  
MARTA D’AGOSTO

To date the genus Diploplastron comprised only one species of ophryoscolecid ciliate, Diploplastron affine, which is characterized by having two retractable ciliary zones in the anterior end of the body, two slender and juxtaposed skeletal plates on the right side, a rod shape macronucleus, and two contractile vacuoles. During study on the characterization of rumen ciliate community composition in Brazilian domestic sheep, we observed ciliates with atypical morphology but with diagnostic features of genus Diploplastron. This study describes Diploplastron dehorityi, a new species of ophryoscolecid ciliate, that differs from D. affine, primarily, in the morphology of skeletal plates, morphology of nuclear apparatus and body shape. In addition to the similarities between the new species and congener species, D. dehorityi has some morphological similarities to species of genus Eremoplastron.


Author(s):  
Margaret A. Highland ◽  
David A. Schneider ◽  
Stephen N. White ◽  
Sally A. Madsen-Bouterse ◽  
Donald P. Knowles ◽  
...  

2011 ◽  
Vol 18 (7) ◽  
pp. 1133-1138 ◽  
Author(s):  
Caroline N. Herndon ◽  
Sudarvili Shanthalingam ◽  
Donald P. Knowles ◽  
Douglas R. Call ◽  
Subramaniam Srikumaran

ABSTRACTMannheimia haemolyticaconsistently causes fatal bronchopneumonia in bighorn sheep (BHS;Ovis canadensis) under natural and experimental conditions. Leukotoxin is the primary virulence factor of this organism. BHS are more susceptible to developing fatal pneumonia than the related speciesOvis aries(domestic sheep [DS]). In BHS herds affected by pneumonia, lamb recruitment is severely impaired for years subsequent to an outbreak. We hypothesized that a lack of maternally derived antibodies (Abs) againstM. haemolyticaprovides an immunologic basis for enhanced susceptibility of BH lambs to population-limiting pneumonia. Therefore, the objective of this study was to determine the titers of Abs directed againstM. haemolyticain the sera of BH and domestic lambs at birth through 12 weeks of age. Results revealed that BH lambs had approximately 18-fold lower titers of Ab against surface antigens ofM. haemolyticaand approximately 20-fold lower titers of leukotoxin-neutralizing Abs than domestic lambs. The titers of leukotoxin-neutralizing Abs in the serum and colostrum samples of BH ewes were approximately 157- and 50-fold lower than those for domestic ewes, respectively. Comparatively, the higher titers of parainfluenza 3 virus-neutralizing Abs in the BH lambs ruled out the possibility that these BHS had an impaired ability to passively transfer Abs to their lambs. These results suggest that lower levels of leukotoxin-neutralizing Abs in the sera of BH ewes, and resultant low Ab titers in their lambs, may be a critical factor in the poor lamb recruitment in herds affected by pneumonia.


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