Judith Fletcher

Light microscope analysis of meiotic prophase chromosomes by silver staining

A method is described for the silver staining of the synaptonemal complex in surface-spread mammalian spermatocytes for light microscope examination. The method is quick, reliable, of broad applicability, and provides a means of making karyotype analysis at meiotic prophase. Many hundreds of suitable cells can be examined in an average preparation in a relatively short space of time. It has so far been applied only to mammalian spermatocytes, but could be used for karyotype analysis in oocytes of mammals and also applied to gonocytes of non-mammalian species.

Cytogenetics and infertility in man*: II. Testicular histology and meiosis

Within a group of 207 subfertile men, selected for testicular biopsy, histological investigations were made successfully in 194 chromosomally normal and 7 chromosomally abnormal individuals. Fifty-two per cent of men with a normal karyotype showed normal testicular histology, 31% showed a general depression of spermatogenesis and 8% showed deficiency in the late stages. Ten per cent had only Sertoli cells in the testis. The range of testicular conditions seen in the chromosomally abnormal men was similar to that found in the chromosomally normal. Meiotic studies carried out on 118 chromosomally normal individuals gave a mean chiasma count of 48-9 per cell. There was a positive correlation between high numbers of cells at diakinesis/metaphase I showing X and Y univalents and low numbers of cells reaching metaphase II. Meiosis was studied in 3 translocation heterozygotes, one 47, XYY male, one 47, XY+mar individual and one patient with a ring Y chromosome.

Translocation heterozygosity and associated subfertility in man

Details of meiotic chromosome studies in four human male translocation heterozygotes are given. All are associated with subfertility. One Robertsonian translocation and one reciprocal autosome translocation appear to be associated with increased levels of abortion. Segregation of unbalanced gametic genomes is thought to be the underlying cause of fetal death. Two other reciprocal autosome translocations are associated with gametogenic failure, leading to azospermia in male heterozygotes.

Meiotic behavior of five human reciprocal translocations

Meiotic studies have been carried out in five human male translocation heterozygotes. An account of the cytological observations is given together with information concerning their reproductive histor

Normal meiosis in two 47,XYY men

SummaryDetails of testicular histology and meiosis are given for two 47,XYY men, one an oligospermic childless individual, the other a fertile man with near-normal spermatogenic activity in his testes. Examination of the chromosomes at meiosis, with “Q” and “C” staining, gave no evidence for the occurrence of the second Y chromosome in the germ line of either individual.

A chromosome rearrangement in an orangutan studied with Q-, C-, and G-banding techniques

A constitutional chromosome rearrangement is a phenotypically normal male organutan is described. The rearrangement resulted from three breakages in chromosome 9 and involved a pericentric inversion and additional reciprocal transpositions of the terminal segments of both arms. Q-, G-, and C-banding studies were carried out, and it was shown that the chromosomes affected was a member of the only pair in the complement that lacked a centromeric C-band and that its G-banding pattern closely resembled that of chromosome 12 in man. The origin of the rearrangement and the role of such rearrangement in producing chromosome polymorphisms are discussed, particularly in relation to evolution and speciation. An additional pair of heteromorphic chromosomes (No.23) is also described. The short arm satellited region of one member of the pair was found to be variable and strongly C-banded.