Human chromosomes, normal and aberrant

Abstract

propose in this paper to give a short account of present knowledge of the human chromosomes and to deal with the subject-matter historically. From slow and certain beginnings extraordinarily rapid advances have developed in recent. The earliest systematic observations on the hum an karyotype were made de Winiwarter (1912) and he disagreed with the nineteenth-century workers, an Flemming and von Bardeleben, who had suggested 24 and 16 respectively for the diploid number. He counted 24 chromosomal objects at the first meiotic division of spermatogenesis. In the second division half the spermatocytes had and the rest had 24. He concluded that the diploid male might have 47 and the male 48 chromosomes and that there was no Y. This interpretation was accepted y Oguma & Kihara (1923) and repeated in a paper by de Winiwarter & Oguma (1926). Painter (1923), in a more extensive investigation, clearly demonstrated the complex in first meiotic divisions but he agreed that there were 23 autosomal nivalents. Most other early observers of spermatogenesis agreed with Painter’s conclusions, otably Shiwago & Andres (1932), Minouchi & Ohta (1934), King & Beams (1936), Koller (1937) and Sachs (1954). Somatic cells in mitosis were examined by Evans & Swezy (1929) and 48 chromosomes were counted, definitely including a Y. Kemp (1929), at the same time, counted chromosomes seen in cultured fibroblasts and dividing somatic cells from human embryos; his results indicated a normal number of 48 but occasionally 47.