Sex Chromosome Analysis Research Articles

Formation of isohaemagglutinins in the marmoset, Tamarinus nigricollis.

THE small South American primates of the Hapalidae family, the marmosets, are unique in that twin births are an almost consistent occurrence1. This twinning phenomenon further is unusual in that all twins appear to be fraternal, and placental vascular anastomoses result in haematopoietic chimerism of the young. Blood chimerism in adult male and female marmosets has been demonstrated by sex-chromosome analyses of cells in metaphase and also by examination of peripheral blood leucocytes for the drumstick-bearing neutrophils2,3. Sex-chromosome analysis of lymph node, spleen and bone marrow cells has also revealed chimerism: thus all haematopoietic tissues are involved3. Erythrocyte chimerism, although presumed to exist, has not yet been demonstrated owing to the unavailability of blood-grouping reagents in this species. Although previous investigations have indicated the presence of human A- and B-like antigens on the marmoset red cells, differences among marmosets of these human blood group substances are not apparent4–6. Tests for naturally occurring isohaemagglutinins in these animals have thus far been negative. The natural blood chimerism assumed to exist in all marmosets because of the twinning phenomenon would appear to preclude or make exceedingly difficult successful red cell isoimmunizations since both donor and recipient could conceivably have two (or more) major genetically distinct blood-group antigens. In a random-bred colony without any breeding records, therefore, the prior knowledge of chimerism in any one animal (as determined by sex-chromosome analysis) could be of considerable value. Thus, if on the basis of sex-chromosome analysis one could find an animal that is definitely a heterosexual chimera, yet in only a small proportion (10–20 per cent), its red cells would be more desirable for immunization purposes in making specific reagents than those of an animal with a relatively high degree of chimerism, or one in which the degree of chimerism is not known. This procedure would have merit only if the degree of chimerism as determined by sex-chromosome analysis of dividing white cells is also representative of the chimerism of the erythropoietic system, an assumption that must be made until evidence shows otherwise. In an analysis of the dividing white cells of the peripheral blood of twenty-six marmosets found to be heterosexual chimeras, two male animals had 12 per cent (No. 21-11-5) and 18 per cent (No. 21-1-1) chimerism of female cells, the lowest observed in our colony. These were then used as red-cell donors for isoimmunizations.

Chromosome studies on spontaneous abortions

1.1. Chromosome studies were performed on the abortuses from 15 cases of induced abortion and 35 cases of spontaneous abortion.2.2. Of the 15 cases of induced abortion, one embryo was found to be a Mongoloid male, 47XY, trisomy G.3.3. Of the 35 cases of spontaneous abortion, there were 20 second trimester abortions. One of these, a uniovular twin with multiple malformations, was a 46/48 mosaic, there being an extra member of the D and G groups in the hyperploid cells.4.4. There were 15 cases of first trimester abortion, and 5 of these had an abnormal karyotype—one trisomy E, one 46XX/45XO mosaic, 2 cases of trisomy A, and one double aneuploidy involving groups D and E.5.5. Chromosome anomalies occur most commonly in first trimester abortions, particularly in association with empty chorionic sacs.6.6. From a review of chromosome studies on 400 cases of spontaneous abortion reported in the literature, the most common abnormal findings are autosomal trisomy (40 cases), triploidy (23 cases), and X monosomy (20 cases).7.7. Spontaneous abortion associated with trisomy occurs most commonly in older maternal age groups.8.8. Sex chromosome analysis has been reported in 327 cases of spontaneous abortion, excluding cases of polyploidy. One hundred and twenty-seven had XX, 135 and XY, and 20 had XO sex chromosome complement.

Sex chromatin and chromosome analysis in the diagnosis of sex abnormalities.

Review1 February 1966Sex Chromatin and Chromosome Analysis in the Diagnosis of Sex AbnormalitiesDOROTHY L. WILLIAMS, M.D., JOHN W. RUNYAN, M.D., F.A.C.P.DOROTHY L. WILLIAMS, M.D.Search for more papers by this author, JOHN W. RUNYAN, M.D., F.A.C.P.Search for more papers by this authorAuthor, Article, and Disclosure Informationhttps://doi.org/10.7326/0003-4819-64-2-422 SectionsAboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissions ShareFacebookTwitterLinkedInRedditEmail ExcerptDuring the past several years there has been much improvement and simplification of cytogenetic techniques. This has helped to remove this field from the realm of basic research and investigation to that of increasing practical importance to clinical medicine. It can now be a valuable aid in the understanding, diagnosis, and sometimes the treatment of abnormalities and syndromes previously poorly understood. Cytogenetics attempts to correlate the microscopic structural and numerical abnormalities of chromosomes with the clinical changes and syndromes associated with them.Since population surveys are now available concerning the known frequencies of specific syndromes, these data at once add...

Hematologic and Cytogenetic Evidence for Hematopoietic Chimerism in the Marmoset, Tamarinus nigricollis

Peripheral blood smears of 20 male and 20 female tamarins were examined for the presence of the nuclear drumstick appendage in neutrophils. This chromatin body characteristic of female cells was found in significant numbers of neutrophils from males and in some females was found to be absent or in a lower frequency than expected. The distribution of drumstick-bearing neutrophils among these animals was such that they suggested male-female blood chimerism resulting from prenatal vascular placental anastomoses between fraternal twins of this species. Heterosexual chimerism was confirmed by sex-chromosome analyses of tissues from both male and female animals. The drumstick marker, however, did not provide a reliable quantitative index of chimerism as determined by sex-chromosome analysis. Chimerism was found in blood, bone-marrow, lymph-node, and splenic tissue indicating intermixing of the hematopoietic systems of fraternal twins. A new micromethod utilizing an in vivo diffusion chamber for the procurement of mitotic cells for chromosome spreads was described.

XY/XXY and sex chromatin positive cell distribution in a 60 mm human fetus.

A 60 mm crown-rump length anatomically normal male fetus is described in which approximately 7 to 19% of the somatic and extraembryonic cells are sex chromatin positive. About an equal percentage of cells grown in culture from various regions of the body were also sex chromatin positive and chromosome analysis of replicate cultures showed that a proportionate number of cells had a total of 47 chromosomes with XXY sex chromosomes. The remaining cells had a normal male chromosome complement. Single sex chromatin positive nuclei or groups of nuclei, sometimes numbering several hundred, were found in the tissues derived from all primary germ layers throughout the entire body and extraembryonic membranes. On the basis of these findings it is suggested that this mosaic condition arose at a very early stage, possibly at the third somatic division, but certainly before tissue differentiation had occurred, through a non-disjunction of a normal male cell. This study sheds some light on the mechanics of embryonic development. The value of the sex chromatin as a marker for detecting mosaic conditions involving the X chromosomes is well illustrated as is the fact that a mosaic can be overlooked when samples are taken from a limited region of the body or if only a small number of cells are studied.