种公牛1/29染色体罗伯逊易位的检测结果及其遗传效应分析

通过对夏洛来、利木赞、西门塔尔三个品种共98头种公牛染色体的遗传检测，在加系夏洛来牛中发现一例1／29染色体罗伯逊易位纯合种公牛及后代1／29罗伯逊易位杂合母牛一例。讨论了1／29染色体罗伯逊易位对繁殖性能的影响。三品种种公牛Y染色体均为中部着丝点，X染色体有中部着丝点和亚中部着丝点两种类型，在品种间呈多态性。     

Incidence of the 1/29 Robertsonian translocation in the cattle population in Czechoslovakia

We studied the inheritance of a serious chromosomal aberration--Robertsonian translocation 1/29 (R.t.1/29) in the female and male progeny of three successive generations after five heterozygous sires, carriers of this chromosomal aberration. Of the total number of 43 progenies that were examined cytogenetically, we found in ten sons of the second successive generation R.t.1/29 in 50% and in 26 daughters in 53%. In the third successive generation we found out this chromosomal aberration in one of two bullocks and in none of five heifers. In all cases we recorded the diploid chromosome number 59,XYt or 59,XXt in heterozygous constitution, in 100% of all examined mitoses. The translocation is of a monocentric type. The results including the data on the fertility of sires do not, however, demonstrate explicitly the reduced fertility of sires with this aberration, or of their progeny, as mentioned by some researchers.     

科尔沁牛染色体14/24易位的初步研究

对内蒙古哲盟地区的5头科尔沁牛进行了细胞遗传学检查。结果:3♀和1♂核型全为2n=60,可配成30对,29对常染色体和1对性染色体,性染色体X为大型亚中着丝粒,Y为小型亚中着丝粒染色体;1♂的核型为异常核型,59,XY,t(14:24)。14/24易位是单独发生的。     

Identification of the 1/29 Robertsonian translocation chromosome in British Friesian cattle

Blood samples for cytogenetic analysis were obtained from 23 animals closely related to a pedigree British Friesian bull which was heterozygous for a Robertsonian translocation, and from 35 of its daughters. The aberration was found in one of its relatives and in 19 (54.3 per cent) of its progeny and was identified as the 1/29 Robertsonian translocation by G- and C-banding techniques. It is considered likely that the translocation formed de novo recently.     

Inheritance of the Robertsonian translocation (1/21) in the Holstein-Friesian cattle. I. Chromosome analysis

A new type of Robertsonian translocation (1/21) was found in Holstein-Friesian breed, and transmitted through the three generations, namely from the bull to 6 out of 11 daughters and 4 out of 7 grand-daughters/sons. Although the father of the bull was not available for cytogenetical studies, it was ascertained that 5 half-sibs of the bull had a normal karyotype. By C-banded karyotypes, the 9 translocation carriers within the three generations had a dicentric centromere in the translocated chromosome. It seems that no morphological effects have been noted to be associated with the translocation in all cases.     

Inheritance of proportionate dwarfism in Angus cattle

OBJECTIVE: To determine the mode of inheritance of congenital proportionate dwarfism in Angus and Angus crossbred cattle, initially detected in two commercial beef herds in northern New South Wales. DESIGN: Matings of normal carrier sires to unrelated cows of diverse breeds, and of one carrier sire to his unaffected daughters. An unrelated Piedmontese bull was also mated to unaffected daughters of the carrier sires. PROCEDURE: Two carrier Angus bulls and nine unaffected daughters, all of whom were completely indistinguishable from normal animals, were purchased for controlled breeding studies under known nutritional and disease conditions. Affected and carrier individuals were examined for the presence of obvious chromosomal abnormalities. RESULTS: Angus dwarfism has been successfully reproduced under controlled experimental conditions over successive years using unrelated dams and is undoubtedly heritable. The high frequency of occurrence of affected individuals (23/61 = 0.38 +/- .06) among the progeny of matings of the Angus sires to unrelated females of diverse breeding is not compatible with recessive inheritance, because of the negligible frequency of proportionate dwarfism in the breeds of the dams. Both paternal and maternal transmission of the defect was demonstrated, so that imprinting in the strict sense of a gene that is only expressed when received from the male parent appears not to be involved. Tested individuals showed no evidence of gross chromosomal abnormality. Dominant autosomal inheritance with incomplete penetrance was indicated by the lack of expression of the defective gene in the two Angus sires and in three unaffected daughters who produced dwarf calves from matings to the Piedmontese bull. CONCLUSIONS: The mode of inheritance is that of a single autosomal dominant gene with a penetrance coefficient of 0.75 +/- 0.12, estimated from the observed incidence of 23/61 affected offspring of the two carrier Angus bulls mated to unrelated dams. Simple genetic models involving either (i) an unstable mutant which changes at high frequency to the expressed dominant dwarfing allele during gametogenesis, or (ii) a dominant allele with penetrance determined by an unlinked modifying locus, are shown to be compatible with the experimental data. Both models indicate that penetrance of the dwarfing gene may possibly be higher in matings involving carrier daughters of the two Angus bulls.     

Y CHROMOSOME MORPHOLOGY OF CATTLE

Metaphase chromosomes from cultured lymphocytes were prepared from 246 bulls including Bos indicus, Bos taurus. Bos (Bibos) banteng, Sanga and interspecific and intra-specific breed crosses. Morphology and karyotype position of the Y chromosome for each bull were noted. Karyotype position of the Y chromosome varied between bulls from 25th to 29th pair and the Y chromosomes of Bos indicus and breeds derived from Bos indicus bulls were acrocentric while those of Bos taurus, Sanga and breeds derived from these bulls were metacentric/submetacentric. Two forms of Y chromosome were noted in the Droughtmaster breed. C-banding patterns of the acrocentric Y chromosome were characteristic and enabled easy identification.     

布尔山羊的染色体核型分析

采用外周血淋巴细胞培养法，对布尔山羊的染色体核型进行了分析。结果表明，布尔山羊的二倍体染色体数目为2n=60，公羊核型为60，XY；母羊核型为60，XX。共有29对常染色体和1对性染色体。所有常染色体均为端部着丝点染色体；X染色体为第二大的端部着丝点染色体，Y染色体为最小的天是唯一的中部着丝点染色体。研究发现，布尔山羊存在1.7％的三倍体和5.9％的四倍体。     

Comparison of two- and three-way rotational crossing, beef x beef and beef x Brown Swiss composite breed production: postweaning growth and carcass traits

Data collected from steer and bull progeny, fed to a constant final feedlot weight over 11 yr, were used to estimate heterosis in post-weaning feedlot growth and carcass traits in two-way and three-way rotational crossing systems and a breed composite from crossing Hereford, Angus and Charolais breeds. Steer and bull progeny from matings of beef x Brown Swiss-cross sires and dams also were compared with the straight beef breeds and beef crosses. Growth traits evaluated were initial weight on test, 112-d weight, total feedlot average daily gain and total days from initial to final weight. Carcass traits included hot carcass weight, dressing percentage, rib eye area, 12th-rib fat thickness, kidney, pelvic and heart fat, yield grade and marbling score. Heterosis estimates for calves of all crossing systems were significant for initial and 112-d weight and for saving of days in the feedlot, but not for average daily feedlot gain. Heterosis estimates were small and nonsignificant for most carcass traits except for fat traits in specific crosses. Males from Hereford and Angus sires mated to Angus x Hereford dams had higher (P less than .10) backfat than did the parental average. Male progeny from Charolais ranked higher (P less than .10 to P less than .01) than calves from Hereford and Angus sires for most growth traits. Progeny from Charolais sires were more desirable (P less than .10 to P less than .01) for traits related to cutability, but they had less (P less than .05 to P less than .01) marbling than calves of Angus sires.(ABSTRACT TRUNCATED AT 250 WORDS)     

Growth traits and composition of two- and three-way-cross intact male progeny of Bos taurus and Bos indicus X Bos taurus dams

Feedlot traits, carcass traits and distribution of commercial cuts of crossbred intact male progeny (n = 556) from young and mature Hereford, Red Poll, Hereford X Red Poll, Red Poll X Hereford, Angus X Hereford, Angus X Charolais, Brahman X Hereford and Brahman X Angus dams were evaluated. First-calf heifers were bred to Red Angus bulls; Santa Gertrudis sires were used for each cow's second and third breeding seasons. Calves from these young dams were slaughtered at 13 mo. Calves of mature dams were all sired by Limousin bulls and slaughtered at 12 mo. Dam breed was a major source of variation in most bull traits. Progeny of Brahman-cross dams were inferior (P less than .01) in daily gain, final weight, carcass weight and in edible cuts/day of age compared with progeny from Bos taurus dams. Intact male progeny of Angus X Charolais dams ranked highest in longissimus area, cutability, and edible cuts/day of age. The range of dam breed means in percentage of steak, roast, bone-in cuts (chuck short ribs and back ribs), short plate and thin cuts, and lean trim was just over 1%. Greater variation among dam breeds existed in fat measurements. Analyses in which Hereford-Red Poll diallel data for young dams and mature dams were combined showed positive maternal heterosis for dressing percentage (P less than .05), carcass weight (P less than .05), carcass weight/day of age (P less than .05), estimated carcass fat (P less than .05), fat thickness (P less than .01) and marbling score (P less than .01). Reciprocal effects were inconsequential. Results illustrate the importance of dam breed-type effects in formulating breeding strategies for commercial beef herds.     

Cleft palate associated with an unbalanced karyotype in piglets sired by a heterozygous carrier boar with a balanced constitutional reciprocal translocation

The progeny of a commercial (Landrace x Duroc) x Large White boar contained a number of piglets with cleft palates. Chromosomal analyses of five affected piglets showed that they all had an identical unbalanced karyotype with partial monosomy of chromosome 16 and partial trisomy of chromosome 3, whereas the normal piglets in the litters had balanced karyotypes. The chromosomal imbalance was the direct result of a constitutional balanced reciprocal translocation carried by their heterozygote sire, described, according to the standard nomenclature, as t(3;16)(q23;q22).     

毛稃偃麦草染色体核型分析

采用根尖压片法对毛稃偃麦草的细胞染色体进行核型分析。结果表明毛稃偃麦草（Elytri-gia alatavica）染色体数目为2n=42,染色体相对长度组成为12L＋4M2＋14M1＋12S,核型公式K（2n）=6 X=42=36m＋6sm（2sat）,属于＂1B＂类型。其中,3对为近中着丝粒染色体,且带有1对随体,其...     

Karyotypes of three shrew species (Soriculus nigrescens,Episoriculus caudatus and Episoriculus sacratus) from Nepal

The karyotypes of three shrew species (Mammalia, Soricomorpha, Soricidae) from Nepal were examined for the first time. Based on the karyotypes and overall differences in skull size, the current Episoriculus caudatus appeared to include two distinct species: the larger E. caudatus and the smaller Episoriculus sacratus. Episoriculus sacratus has three subspecies, E. s. soluensis in Nepal and Sikkim, E. s. umbrinus in Assam, Myanmar and the Yunnan Province of China, and E. s. sacratus in the Sichuan Province of China. Soriculus nigrescens had a diploid chromosome number (2n) and fundamental number (FN), including two X chromosomes, of 64 and 92, respectively, consisting of 11 metacentric or submetacentric, two subtelocentric and 18 acrocentric pairs of autosomes, a metacentric X and an acrocentric Y chromosome. Episoriculus sacratus soluensis had 2n = 74 and FN = 126, consisting of 12 metacentric or submetacentric, 13 subtelocentric and 11 acrocentric pairs of autosomes, a submetacentric X and an acrocentric Y chromosome. Episoriculus caudatus had 2n = 60 and FN = 118, consisting of 19 metacentric or submetacentric, nine subtelocentric and one acrocentric pair of autosomes, a subtelocentric X and an acrocentric Y chromosome. The karyotypes of these three species are characterized by their large 2n and FN values compared with other Soricidae.     

Maternal characteristics of young dams representing Bos taurus and Bos indicus x Bos taurus breed types

Reproductive traits and preweaning growth of progeny from young Hereford, Red Poll, Hereford X Red Poll, Red Poll X Hereford, Angus X Hereford, Angus X Charolais, Brahman X Hereford and Brahman X Angus dams were evaluated. First-calf heifers were mated with Red Angus bulls; Santa Gertrudis sires were used for each cow's second and third breeding season. Herefords, Red Polls and Hereford-Red Poll crosses were below average in percentage of calves weaned, whereas Angus-sired and Brahman-sired dams exceeded the overall mean. Angus X Charolais (P less than .10), Brahman X Hereford (P less than .01) and Brahman X Angus (P less than .10) dams weaned a higher percentage of calves than straightbred Herefords. None of these breed types differed from young Angus X Hereford females in reproductive performance. Angus X Charolais calves ranked highest in 180-d calf weight, exceeding progeny from both Hereford (P less than .01) and Angus X Hereford (P less than .10) dams. Brahman X Hereford dams weaned heavier (P less than .05) calves than Herefords, but their progeny did not differ at weaning from those reared by Angus X Herefords. Calves from Brahman X Angus dams weighed 12.7 kg less (P less than .01) than Angus X Hereford progeny. Analysis of the Hereford-Red Poll diallel showed evidence of (P less than .10) maternal heterosis in 180-d calf weight.(ABSTRACT TRUNCATED AT 250 WORDS)     

C- AND G- BANDING PATTERNS AND CHROMOSOMAL MORPHOLOGY OF SOME BREEDS OF AUSTRALIAN CATTLE

A cytogenetical study using metaphase chromosomes from cultured lymphocytes, was made of 2 Banteng (Bibos banteng) steers and 218 bulls representing 13 purebreeds (Bos taurus type, Bos indicus type and Sanga) and 7 cross-breeds. Studies were made of photographic karyotypes of Giemsa stained and C-banded chromosomes of bulls of each breed and of B-banded chromosomes from 3 breeds of Bos indicus and one cross-breed Australian Friesian Sahiwal) cattle. The relative lengths of chromosomes of Bos taurus and Bos indicus bulls were compared and significant difference in relative lengths of the X chromosomes were noted between these two species. There was a differences in morphology of the Y chromosomes; Sanga, Banteng and Bos taurus type breeds had a small submetacentric Y chromosome, except for the Jersey which had a metacentric Y chromosome. All Bos indicus type bulls had an acrocentric Y chromosome but the Droughtmaster breed had two forms of the Y chromosome (submetacentric and acrocentric). The C-banding patterns of the autosomes and X chromosomes were similar for all breeds while those of the Y chromosomes of Bos indicus type cattle allowed their accurate identification. G-banding patterns of Bos indicus resembled those of Bos taurus and enabled pairing of homologous chromosomes. Centromeres of the autosomes were unstained but those of the sex chromosomes were darkly stained.     

1/25 translocations in Blonde d'Aquitaine cattle in New Zealand

A Robertsonian centric fusion between chromosomes 1 and 25 in Blonde d'Aquitaine cattle in New Zealand is reported. This fused chromosome is the same as the widely reported 1/29 translocation chromosome with the difference in the numbering arising from inconsistencies in the G and R-banded cattle karyotypes of the International System for Cytogenetic Nomenclature of Domestic Animals, 1989.     

CEREBELLAR HYPOPLASIA OF GENETIC ORIGIN IN CALVES

Within 2 years, following the introduction of 2 Shorthorn bulls from the same stud into an Australian Illawarra Shorthorn (AIS) herd, 16 calves were born with cerebellar hypoplasia. All affected calves were the progeny of one bull mated to the daughters of the other. All other progeny of these bulls, most of which were from AIS dams, were normal. Affected calves exhibited severe ataxia, consistent head movement and abduction of the forelimbs. Microscopic changes in the cerebellum included sparsity of cells of the granular layer, loss of Purkinje cells and narrowing of the molecular layer. Observations on the frequencies of normal and abnormal calves are consistent with the hypothesis that the condition is caused by an autosomal recessive gene for which affected calves were homozygous and which was introduced into the herd in heterozygous condition by both of the Shorthorn bulls. Evidence is given for an unusually high frequency of the gene in the stud of origin of the Shorthorn bulls and a procedure for reducing its frequency is outlined. The possibility of a viral or toxic aetiology is discussed but is considered to be an unlikely explanation for the condition in this herd.     

Chromosomes of gaur cross domestic cattle hybrids

The chromosomes of five gaur (Bos gaurus hubbacki) domestic cattle (B indicus cross B taurus) hybrids (three females, two males) were studied using the leucocyte culture method and centromeric (C) banding technique. All the hybrids had a diploid chromosome number of 2n = 58, made up of two submetacentric autosomes (different in size) and 54 acrocentric autosomes, most of which could be arranged in pairs in descending order of size. The sex (X) chromosomes in females were a pair of submetacentric chromosomes smaller than the submetacentric autosomes. The Y chromosome in males was a small submetacentric chromosome. The C banding patterns were useful in identifying the X and Y chromosomes and the inherited submetacentric autosomes from the gaur sire. Phenotypically, the hybrids resembled normal B indicus cross B taurus calves except for the presence of a distinct hump-like dorsal ridge containing the spinous processes of the third to 11th thoracic vertebrae, upright 'deer-like' ears and long lean legs. The potential of these hybrids as important genetic resources for meat production is stressed.     

Life-cycle evaluation of Bos taurus and Bos indicus X Bos taurus breed types in a dry, temperate climate: performance of mature dams

Mature dams representing Hereford, Red Poll, F1 Hereford x Red Poll, F1 Red Poll x Hereford, F1 Angus x Hereford, F1 Angus x Charolais, F1 Brahman x Hereford and F1 Brahman x Angus breed types were evaluated. All cows were bred to Limousin sires to produce two-way or three-way-cross progeny. Mature Brahman x Hereford dams produced a higher (P less than .05) percentage of live calves than Herefords, but dam breed differences in percentage of calves weaned relative to the number of cows exposed for mating were not statistically significant. Progeny of Angus x Charolais and Red Poll dams were outstanding in weaning weight, but Hereford and Brahman-cross calves were below average. Planned comparisons showed that Angus x Charolais calves were heavier (P less than .01) at weaning than Hereford (23.0 +/- 3.8 kg) or Angus x Hereford (9.6 +/- 3.2 kg) progeny. Mature Angus x Hereford mothers weaned heavier calves than did Brahman x Herefords (7.4 +/- 3.2 kg, P less than .05) or Brahman x Angus (10.9 +/- 3.0 kg, P less than .01). Analysis of the Hereford-Red Poll diallel showed evidence of maternal heterosis in calf weaning weight (4.0 +/- 2.6 kg, P less than .05), but there was no difference in the percentage of calves weaned by crossbred vs straightbred dams.(ABSTRACT TRUNCATED AT 250 WORDS)     

屏边大围山原鸡染色体核型分析

采用直接骨髓法制备云南屏边大围山原鸡染色体,并对其进行核型研究,结果表明,屏边大围山原鸡染色体数目2n=78, 前10对为大染色体,后29对为微小染色体,性染色体为ZZ(♂)／ZW(♀)型;根据前5对染色体相对长度、臂比值及着丝点指数的测量结果,各染色体的形态为：1号、2号和Z染色体为中央着丝粒（m）染色体,3号为端着丝粒（t）染色体,4号为亚中央着丝粒（sm）染色体。