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PubMed1999

Transposon dynamics and the breeding system.

The selfish DNA hypothesis predicts that natural selection is responsible for preventing the unregulated build up of transposable elements in organismal genomes. Accordingly, between-species differences in the strength and effectiveness of selection against transposons should be important in driving the evolution of transposon activity and abundance. We used a modeling approach to investigate how the rate of self-fertilization influences the population dynamics of transposable elements. Contrasting effects of the breeding system were observed under selection based on transposon disruption of gene function versus selection based on element-mediated ectopic exchange. This suggests that the comparison of TE copy number in organisms with different breeding systems may provide a test of the relative importance of these forces in regulating transposon multiplication. The effects of breeding system also interacted with population size, particularly when there was no element excision. The strength and effectiveness of selection against transposons was reflected not only in their equilibrium abundance, but also in the per-site element frequency of individual insertions and the coefficient of variation in copy number. These results are discussed in relation to evidence on transposon abundance available from the literature, and suggestions for future data collection.

Breeding↗
PubMed2000

[Estimates of breeding value of Inner Mongolia cashmere goats using animal model BLUP method].

In this study, single trait animal model of best linear unbiased prediction (BLUP) procedures was used to obtain estimates of 3,981 Inner Mongolia cashmere goats' breeding value for body weight and cashmere yield. The data were collected during 1989-1998 at Arbas cashmere goats farm, Etuoke banner, Inner Mongolia. Multiple traits of BLUP were used to get estimates of total breeding values (TBV) of all goats. The model included age and sex-herd-year as fixed effects, and individual additive effect and individual permanent environment as random effects. The selection based on breeding value and phenotypic value was compared. The results showed as following: (1) There was a large difference between weaning weight selection and TBV selection of ram lamb; (2) The difference between phenotypic selection and TBV selection of gimmer hogg reached a significant level (P < 0.01); (3) The difference between phenotypic selection and TBV selection of ram hogg reached a significant level (P < 0.01); (4) Rank correlation between body weight selection and body weight' EBV selection and that between cashmere yield selection and cashmere yield' EBV selection were not significant (P > 0.05). The study concluded precision of individual phenotypic selection was low and animal model BLUP was suitable to select Inner Mongolia cashmere goats. At last, this study gave a series of methods of selecting sires based on objective reality.

Animals↗
PubMedDate not supplied

[Breeding biology of the whiskered auklet (Aethia pygmaea): postnesting period].

This is the third paper on the breeding biology of the whiskered auklet on Buldir Island (Aleutian Islands) based on material collected in 1993. Unlike other alcid birds, both adult and young whiskered auklets returned to the colony the night after the end of the breeding season. From the end of July until the third ten-day period of August, the number of adult birds that returned to the island was at approximately the same level, and then decreased, while the number of young birds that returned to the islands markedly varied, and peaks were noted every 5-8 nights. Adult birds continued to visit all the nest habitats, but not all nest chambers were visited equally frequently. In the first and third ten-day periods of August, the auklets visited 61% and 19.8% of the nest chambers, respectively. It remains unclear whether they were their hosts, or other birds used their nests for the next year. The return of adult and young birds to the colony to sleep after the breeding season appears to be related to the settled mode of life of the whiskered auklet and its feeding near the islands in water perturbations caused by tidal currents.

Animals↗
PubMedDate not supplied

Interrelations of organism prevalence, specimen collection method, and host age, sex, and breed among 8,354 canine urinary tract infections (1969-1995).

Selected information was compiled from canine urinalyses and urine cultures conducted between January 1969 and December 1995. Eight thousand three hundred fifty-four microbial isolates (bacteria and fungi) included 4,873 isolates from females and 3,481 from males. Ten bacterial genera accounted for 96.3% of the urinary isolates, including Escherichia coli (44.1%), Staphylococcus spp. (11.6%), Proteus spp. (9.3%), Klebsiella spp. (9.1%), Enterococcus spp. (8.0%), and Streptococcus spp. (5.4%) as the 6 most common isolates in both genders of dogs. Among these 6 genera, female dogs were generally predisposed over males, although males had more urinary tract infections (UTIs) caused by Klebsiella spp. Distributions of ages at UTI diagnosis tended to be similar between genders. Infection with a single microbial species was responsible for >72% of UTIs in both genders. Among females, 40 breeds and a mixed-breed group represented 90.2% of all positive urine cultures, 88.4% of the individual dogs with UTIs. and 88.2% of the microbial isolations. Among males, these same 41 breed groups represented 87.9% of all positive urine cultures, 87.6% of the individual dogs, and 88.2% of the microbial isolations.

Age Distribution↗
PubMed2001

[Studies of genetic diversity of Zhejiang native chicken breeds].

A total of 539 bases of mitochondrial DNA D-loop region of five native chicken breeds of Zhejiang province and the white leghorn chicken (as the control) were sequenced by DNA sequencing technique, and the phylogenetic trees of the chicken breeds were constructed. The results showed that 24 variation sites i.e. 4.45% sequence divergence were detected among the 30 DNA sequences, and the six breeds belonged to two different maternal lineage, one included Xianju chicken and White Leghorn chicken which had the same maternal origin, the other included Lingkun chicken, Baiyiner chicken, Wugu chicken and Xiaoshan chicken which had the same matriarchic ancestor. Among the latter lineage, Lingkun chicken, Baiyiner chicken and Wugu chicken had a closer relationship to each other than to Xiaoshan chicken.

Animals↗
PubMed2001

Effect of acrosomal defects on fertility of bulls used in artificial insemination and natural breeding.

Four bulls that produced spermatozoa with a high percentage of abnormal acrosomes were individually placed in pens with females for 21 days. Frozen semen from 2 of the bulls was used for artificial insemination. One of the bulls was placed in a competitive mating situation with normal bulls at pasture. First service pregnancy rates were determined by transrectal ultrasonography 28 days after bull removal from breeding pens, or after the last artificial insemination. The results of competitive mating at pasture were determined from breeding observations, the phenotypic characteristics of calves sired, and blood typing for parentage. The results of these studies suggest that bulls that produce a high percentage of spermatozoa with indented acrosomes may have normal fertility when used in artificial insemination or in single sire mating; however, their fertility may be low when breeding competitively with bulls with normal spermiograms.

Acrosome↗
PubMed2001

[Analysis on single nucleotide polymorphisms of porcine myostatin gene in different breeds].

By PCR-RFLPs and PCR-SSCP approach, three single nucleotide polymorphisms (SNPs) of porcine myostatin gene (MSTN) were analyzed in different breeds including "doubled-muscled" Yorkshire, Yorkshire, Landrace, Hamshire, Duroc, Piteran, Erhualian, Min, Hubei White and some hybrids. The three SNPs were located in the 3' encoding region, 5' promoter region and intronl region respectively. For the SNP in the 3' encoding region, which was caused by C-->T transition, the mutation frequency was relatively low: no TT genotype was detected in 274 individuals of different breeds. For the SNP in the 5' promoter region, 560 pigs were investigated. The allele T dominates in the imported lean-type pig breeds such as Yorkshire, Landrace, Duroc, Hampshire, Piteran and hybrid, however, in Erhualian and Hubei White pigs, the allele A was in majority. Polymorphism showed the similar pattern for the SNP in intron 1 region. G was the dominant allele in Yorkshire, Landrace and their hybrids, while in Erhualian and Hubei White pigs the frequency of A was much higher. Obviously they were not in Hardy-Weinberg equilibrium state. For Min and Yorshire x Erhualian pigs, they were in Hardy-Weinberg equilibrium state for the SNPs in the 5' promoter region and (or) intron 1 region. The frequency for the A alleles of SNPs in the 5' promoter region and intron 1 region was higher for "double-muscled" Yorkshire than for Yorkshire and linkage for these two mutation sites was also observed.

Animals↗
PubMed2001

[The achievement of industrialized healthy aquatic breeding of hippocampus and its application prospects].

The artificial industrialized aquatic breeding of Hippocampus, which is a kind of Chinese medicinal marine material, has been achieved in the artificial aquatic breeding base of Hippocampus of Guangdong Richvast Group Company since 1983. This article reported part of the achievements of the large-scale artificial aquatic breeding experiments. The prospects for the research and application of Hippocampus as health foods and drugs were also analyzed.

Animals↗
PubMedDate not supplied

[Molecular and genetic polymorphism in three cattle breeds].

Determination of cattle breed and assignment of individual animals to that or another group based on distinctions of genotype is of great importance in genetics and selection. Using of PCR-analysis opened new possibilities for typing DNA. The procedure of PCR was optimized for animal DNA. Two methods of PCR, RAPD and SSRP, were applied for investigation of molecular-genetical polymorphism in three cattle breeds (Ukrainian red-motley lactescent, Golshtine and Simmental). A dendrogram reflecting genetical mutual relations between analyzed animals was drawn. The level of homo-heterozygosity and the distribution of microsatellite alleles were determined. System for investigation of molecular-genetical polymorphism in the cattle breeds and characterization of genotype of individual animals were developed and tested on a real population.

Animals↗
PubMed1975

The effects of parity, litter size, season, and breeding protocol on the number of DBA/2J Ten mice available for weaning.

Data on the reproductive behavior of DBA/2J Ten mice, collected from October 1970 through March 1973 and utilizing a 2-female, 1-male breeding system, with the mice remaining together throughout their reproductive life indicates: a) Litter size tends to increase through the fourth litter, the first litter being much smaller than successive litters; b) Survival rates of litters with 2--4 pups increase with successive deliveries; c) Survival rates of litters with 5--9 pups are approximately the same regardless of parity; d) There is a circannual rhythm in the number of pups available for weaning da 21, which is attributable to changes in postnatal viability. Data collected using a breeding pen system, with isolation of females pre- and post-delivery (March 1973 to March 1974) indicates: a) There is a reduction in live litter sizes in later litters with this system; b) There is a large reduction in the proportion of pups surviving to weaning with this system when compared with the other breeding system.

Animals↗
PubMed2002

Factors affecting breeding soundness classification of beef bulls examined at the Western College of Veterinary Medicine.

Breeding soundness evaluation records from 2110 beef bulls, for the period of 1986 to 1999, were analyzed to determine the prevalence and importance of factors affecting breeding soundness classification. The percentage of all bulls classified as satisfactory ranged from 49.0% in January to 73.3% in May. The percentage of physically normal bulls with satisfactory semen quality ranged from 65.7% in January to 87.5% in June. Poor body condition or excessive body condition, below average or below the recommended minimum scrotal circumference, lameness, and severe scrotal frostbite significantly reduced the probability of a satisfactory breeding soundness classification. The percentage of sperm with midpiece defects declined significantly and the percentage of sperm with head defects increased significantly with the approach of summer. Photoperiod, cold stress, poor or excessive body condition, and reduced feed quality may interact to reduce semen quality in the winter months.

Aging↗
PubMed2002

[Breeding for digenic apple resistance to scab].

The results of the apple breeding for digenic resistance to scab (1979-2000), which is more long-term than the monogenic breeding, have been reviewed. The hybrid seeds obtained from the reciprocal crossing between the Vf and Vm resistance gene donors served as the original material. The seed progeny yielded by backcrosses between these hybrids and the susceptible cultivars were examined (age--first true leaves) using inoculation in a greenhouse. The following criteria were proposed for breeding parental forms and the cultivars of the VfvfVmvm genotype: (1) phenotype segregation in the progeny of three resistant: one susceptible seedling and (2) the presence in the progeny of two types of resistant seedlings: those with the class 1 resistance (points and spots-hypersensitivity) typical of the Vm gene and those with the class 2-3 resistance (chlorotic and necrotic spots) typical of the Vf gene.

Breeding↗
PubMedDate not supplied

[ISSR-PCR in differentiation of gene pools of cattle breeds].

The genetic structure of five cattle breeds from Ukraine was investigated using ISSR-PCR method. Breeding- and sex-specific spectra of amplification products were revealed with two threenucleotide microsatellite primers. The possibility of using ISSR-PCR markers for characterization of genetic relations between breeds of cattle were evaluated.

Animals↗
PubMed2001

[Systemic breeding of the new variety of Biantiao ginseng (Panax ginseng)].

OBJECTIVE: To breed new varieties of Biantiao ginseng for high yield and fine quality. METHODS: Systemic breeding methods were applied. About 3,000 outstanding Biantiao ginseng roots were selected and planted in breeding field, and self-crossed for four generations. During the course, inferior lines or plants were rejected. Then strain comparison, identification of resistance to black-speck disease, and analysis of active compositions were carried out. RESULTS: "Biantiao 1" (BT1), the first new variety of Biantiao ginseng, with green stems and thick, long, elegant roots and median resistance to black-speck disease, has been harvested since 20 years. The percentage of Biantiao ginseng roots and yield were 15% and 30% higher than the control's respectively. The content of total ginsenosides and the main monomers was 1.8%-2.5% higher than the control's. The characteristics of overground part and root of BT1 were uniform and stable. CONCLUSIONS: BT1, a new excellent ginseng variety, has a good potential value to be generalized in ginseng production.

Breeding↗
PubMed1992

An attempt to eradicate Herpesvirus simiae from a rhesus monkey breeding colony.

In the fall of 1987 an attempt to establish a Herpesvirus simiae (B-virus)-negative rhesus monkey (Macaca mulatta) breeding colony was initiated at the Armstrong Laboratory. A serologic testing program was used to identify all monkeys into groups that were either positive or negative to B-virus based on serologic tests. Segregation of the groups allowed the creation of breeding harems that were exclusively seropositive or -negative to B-virus. Animals that were serologically positive were kept in breeding to maintain infant production levels not unlike those previous to segregation. Decreasing numbers of animals converted to a positive status during the first three serum tests for B-virus in the program. During 1990, an increase in the number of monkeys converting to positive status and the discovery of an indeterminate status demonstrated that latency of B-virus in the rhesus may have the potential to defeat an eradication attempt not conscientiously pursued.

Animal Husbandry↗
PubMed1992

Influence of hormonal secretion and fertility in merino mutton sheep by exogenous pheromone application during the breeding season.

The effect of a ram-pheromome extracted from the wool of insemination rams with excellent libido sexualis of the merino mutton sheep breed was examined with respect to the hormonal secretion and fertility of adult ewes during the breeding season. A control group (untreated animals) was at disposal for every experiment. There were significant differences between the ewes treated with pheromone and the controls in the course of the preovulatory LH wave and the oestradiol concentration of the oestrus sheep at the beginning of the breeding season. The ovulation in ewes after prostaglandin application was stimulated by pheromone applications. The regime practised in the experiment on pherome application had a positive influence on the conception rate of the inseminated ewes and resulted in a significant increase of the lambing results (lambs/birth).

Aerosols↗
PubMed1992

Breeding habitats and their contribution to Anopheles stephensi in Panaji.

A one-year longitudinal study conducted in 9 categories of breeding habitats in Panaji, Goa, showed that 1.1% of the 67,360 breeding sites contained Anopheles stephensi immatures and the overall positivity varied from 0.4 to 3.5% with a peak in June. The habitat-wise proportion of An. stephensi was: wells, 0-1.3%; fountains, 1.4-11.4%; masonry tanks, 0.8-6.1%; overhead tanks, 0.1-4.0%; curing water in construction sites, 0.6-9.0%; groundwater tanks, 0-1.4%; tyres, 0-8.9%; barrels and tins, 0-5.4%; and intradomestic containers, 0-1.9%. An. stephensi was breeding along with An. subpictus, An. vagus, An. barbirostris, Culex quinquefasciatus, Cx. vishnui, Ae. aegypti, Ae. albopictus and Ae. vittatus.

Animals↗
PubMedDate not supplied

[Use of genetic markers in breeding of a commercial cattle herd].

Combination of type estimation and use of immunogenetic markers to analyze genotypes of breed animals permits intensifying breeding and promotes more rapid obtaining of the desired inherited material. It is suggested to carry out breeding in commercial cattle herds under constant immunogenetic control.

Alleles↗