摘要:

Computer programs of both a statistical and logical nature were applied to the problem of human karyotyping. A linear discriminant function was calculated based on karyotyping and measurements made by an experienced cytogeneticist on 50 spreads, the design set, and this function was tested on a further 50 spreads, the test set. All the spreads used were from normal human females, but the procedure could easily be extended to male karyotyping, providing the appropriate ‘male’ or ‘female’ program is used in a given case. The only input measurements required and used in the design and test sets were the four arm lengths of each chromosome, measured and supplied to us as four single straightline segments from the centromere to the ends of the arms to simulate contemplated computer measurements. The analysis was done in two stages; the first assigned each chromosome into one of eight groups by its individual characteristics. The second reassigned the 46 chromosomes of each spread so that each group in each spread had its correct number corresponding to a normal human karyotype. The results of the first stage of the computer analysis disagreed with the cytogeneticist 8% of the time in the design set and 9% of the time in the test set. The second stage proved successful in decreasing this disagreement to 6% and 7% respectively. The discriminant function found and the reassignment algorithm can serve as a karyotyping system which is both quantitative and objective. It requires only arm-length measurements to be made. With computer assistance in making these and possible additional independent measurements, such a system appears promising as a basis for automating chromosome a

ISSN:1424-8581    

DOI:10.1159/000130045

出版商:S. Karger AG    

年代:1969

数据来源: Karger

摘要:

Fresh semen from swine was exposed to 600 r of X-irradiation and used to inseminate sows. The chromosomes of the resultant liveborn progeny were studied through the use of leukocyte cultures. Of the 31 pigs studied, 4 had consistent large aberrations in all of the 30 cells studied per animal. Three of these aberrations were translocations; the other was a pericentric inversion. These were thought to be attributable to immediate effects of X rays. An interesting mosaic condition was seen in three of the pigs studied. It was apparently inherited, at least in two of them. All of the pigs had a breakage-deletion condition for the same chromosome. Among the delayed effects of X-irradiation were chromosome alterations including aneuploidy, fragments, chromosome breaks, chromatid breaks and chromosome gaps. Other traits studied were chromatid gaps, secondary constrictions, pericentric inversions and sister chromatid fusions. The independent variables included in the analyses of variance were X-irradiation, breed, sex, irradiation × sex interaction and breed × sex interaction. The effects of these independent variables were not lucid, but there were some conclusions drawn. X-irradiation had a threshold effect, with the effect being a suppression of aberrations. Females, when interacting with the irradiation or breed effects, had higher frequencies of aberrations than males. Breed effects were not consistent, and no trend was apparent. Of the nine dependent variables studied, only fragments and chromosome breaks were noticeably correlate

ISSN:1424-8581    

DOI:10.1159/000130046

出版商:S. Karger AG    

年代:1969

数据来源: Karger

摘要:

The study of a bovine freemartin and its male co-twin has shown that the sex-reversed gonads of the female are secreting testosterone. Therefore, we suggest that the masculinisation of the freemartin’s reproductive tract may be due to sex hormones secreted by its own gonads, rather than by those from its male co-twin. On the evidence at present available, we favour the view that the female gonad is sex-reversed by a humoral inductor substance coming from the male co-twin that causes retention of the medullary sex cords. A study of the male co-twin suggests that its gonads may also be abnormal in that they secrete reduced amounts of androgen. Both twins showed extensive 60, XX/60, XY chimaerism, with a metacentric marker chromosome associated with the XY cell line only. This was derived from the dam. The proportion of XY cells varied markedly between tissues in both the twins. We were unable to find any germ cells in the female gonad, and, with the exception of one possible female pachytene, all the germ cells examined in the male’s testes were

ISSN:1424-8581    

DOI:10.1159/000130047

出版商:S. Karger AG    

年代:1969

数据来源: Karger

摘要:

Clinical, cytogenetic and other laboratory studies are reported in a set of dizygous twins, their parents and siblings. The proposita was a girl with profound mental deficiency of unknown cause; she had been born with a placenta showing marked chorangiomatosis. In addition, she was found to have a chromosomal error consisting of a translocation of material of the long arms of a No. 2 chromosome to the long arm of a No. 15 chromosome. Studies of normal marker loci failed to provide evidence that any of them had been lost or inactivated as a consequence of the translocation.

ISSN:1424-8581    

DOI:10.1159/000130048

出版商:S. Karger AG    

年代:1969

数据来源: Karger

ISSN:1424-8581    

DOI:10.1159/000130049

出版商:S. Karger AG    

年代:1969

数据来源: Karger