56 



BIOLOGIC BASIS OF SEX 



suspected. In the syndrome of seminiferous- 

 tubule dysgenesis where there is tubular 

 fibrosis, 9 are listed as male and 18 female. 

 Where there is germinal aplasia, 15 are 

 listed as male and 1 as female. The seeming 

 difficulties in assigning a sex constitution 

 to some of these types are now being dis- 

 sipated through the study of the full chro- 

 mosome complements which are responsible 

 for these different disease conditions. As ob- 

 servations on different chromosome types 

 have been extended, evidence has accumu- 

 lated to show that the numbers of sex nuclear 

 chromatins, for at least some of the nuclei 

 making up the organism, often equals 

 (n — 1) times the number of X chromo- 

 somes. The majority of male XY nuclei are 

 chromatin negative as are most of the Tur- 

 ner XO type. Female nuclei XX have a sin- 

 gle chromatin positive element as do the 

 XXY and XXYY types. The XXX and 

 XXXY have 14 and 40 per cent respectively 

 with two Barr bodies in cases for which 

 quantitative data are available. However, a 

 child with 49 chromosomes, but whose cul- 

 tured cell chromosomes appear as single 

 heteropycnotic masses making identification 

 of the individual chromosomes difficult, 

 showed 50 per cent of the cell nuclei with 

 three Barr elements (Fraccaro and Lindsten, 

 1960) . The chromosome constitution of these 

 nuclei was interpreted as trisomic for 8, 11, 

 and sex chromosomes. Sandberg, Cross- 

 white and Gordy (1960) report the case of a 

 woman 21 years old having various somatic 

 changes which does not fit this sequence. The 

 chromosome number was 47 and the nuclei 

 were considered trisomic for the sixth largest 

 chromosome. Two chromatin positive bodies 

 were ])rosent in the nuclei. 



2. Chrotnosome Complement und Phenotijpe 

 in Man 



Experience of the past 50 years has em- 

 phasized that genes and trisomies or other 

 types of aneuploid chromosome complexes 

 may lead to the development of abnormal 

 phenotypes expressing a variety of charac- 

 teristics. Drosophila led the way in illustrat- 

 ing how the different gene or chromosome 

 arrangements may affect sex expression. In- 

 vestigations of human abnormal types, par- 

 ticularly those with altered sex differentia- 

 tion, have reccntlv .^liown that man follow.-^ 



other species in this regard. The Y carries 

 highly potent male influencing factors. Gene 

 differences often lead to characteristic phe- 

 notypes of unique form. 



3. Testicular Feminization 



The testicular feminization syndrome il- 

 lustrates one of these types. As described by 

 Jacobs, Baikie, Court Brown, Forrest, Roy, 

 Stewart and Lennox (1959), "In complete 

 expression of this syndrome the external 

 genitalia are female, pubic and axillary hair 

 are absent or scanty, the habitus at puberty 

 is typically female, and there is primary 

 amenorrhoea. The testes can be found either 

 within the abdomen, or in the inguinal 

 canals, or in the labia majora, and as a rule 

 the vagina is incompletely developed. An 

 epididymis and vas deferens are commonly 

 present on both sides, and there may be a 

 rudimentary uterus and Fallopian tubes. 

 The condition is familial and is transmitted 

 through the maternal line." A sex-linked 

 recessive, a sex-limited dominant, and chro- 

 mosome irregularities of the affected per- 

 sons have been postulated as mechanisms 

 causing the apparent inheritance of this 

 condition. Chromosome examinations of the 

 cells of affected persons have shown 46 as 

 the total number and X and Y as the sex 

 complement. The karyotype analysis agrees 

 with the Barr nuclear chromatin test in 

 that the cells are chromatin-negative but 

 both are at variance with the sex pheno- 

 types in the sense that aside from sup- 

 pressed testes the patients are so completely 

 female. Genetically, Stewart (1959) has de- 

 scribed two color-blind patients with the 

 testicular feminization syndrome in the first 

 five patients he reported. The limited data 

 from these cases suggest that the genie basis 

 for this condition is either independent or 

 but loosely linked with color blindness. This 

 evidence does not exclude sex-linkage but 

 does make it less probable. The third hy- 

 pothesis of autosomal inheritance may take 

 one of several forms. A recessive gene which 

 affects only the male phenotypes when in 

 homozygous condition is apparently un- 

 tenable because the matings from which 

 these individuals come are of the outbreed- 

 ing type and the ratios apparently do not 

 differ from the one-to-one ratio expected of 

 a heterozygous dominant instead of that re- 



