: DEPARTURES FROM DIPLOIDY ____________________________________________________________________ The diploid chromosome complement of Drosophila melanogaster may be designated X/X; 2/2; 3/3; 4/4 for females and X/Y; 2/2; 3/3; 4/4 for males. Addition to or subtraction from either of these complements of one or more chromosomes produces a depar- ture from diploidy. The non-diploid constitutions are desig- nated by a name but not a symbol except as included in the name, e.g., X/0 male. Constitutions are described by listing their component chromosomes, homologous chromosomes being separated by slash bars and nonhomologous chromosomes by semi- colons. When two homologous chromosomes are attached to the same centromere, components are listed without separation, e.g., XX, XY, and 44. # diploid metafemale constitution: X/X/X; 2/2; 3/3; 4/4; sex chromosome constitution may also be XX/X. source: Produced by triploid and compound-X-bearing females. May result from two-X gametes produced by nondisjunction. discoverer: Bridges. synonym: superfemale. references: 1921, Science 54: 252-54. 1922, Am. Nat. 56: 51-63 (fig.). 1925, Am. Nat. 59: 127-37. Morgan, Bridges, and Sturtevant, 1925, Bibliog. Genet. 2: 153-62 (fig.). properties: Wings crumpled or incised on inner margin. Rear legs often malformed. Viability low, usually less than 0.5%. Flies die mostly in late larval and pupal stages; at 25C, puparium formation delayed 1-2 days (Brehme, 1937, Proc. Soc. Exp. Biol. Med. 37: 578-80). Survival increased by rearing at 20 instead of 25; five days after oviposition most sensitive (Neeley, 1968, DIS 43: 83; 1969, Genetics 61: s43). Sur- vivors sterile; two fertile metafemales were apparently mosaic for triploid tissue [Rolfes and Hollander, 1961, J. Heredity 52: 61-66 (fig.)]. Larval ovaries from metafemales tran- splanted into sterile diploids have produced a few progeny (Beadle and Ephrussi, 1937, Proc. Nat. Acad. Sci. USA 23: 356-60). Crossing over between the X chromosomes appears to be infrequent. Studies of C(1)RM/R(1)wvC//C(1)RM/0 mosaics (Schupbach, Wieschaus, and Nothiger, 1978, Wilhelm Roux's Arch. Dev. Biol. 184: 41-56) demonstrate the focus of lethal- ity to be in a region near the ventral prothoracic discs and that of female sterility to be in the external genitalia. Mosaics with diploid external genitalia and 3X:2A germlines produce about three-fourths as many eggs as diploid females but only two percent of such eggs develop into adulthood, most of them failing to complete embryogenesis. Transcriptional activity of each X chromosome in 3X:2A larvae, as measured by uridine incorporation by polytene chromosomes, is two-thirds that of each X in 2X:2A larvae according to Lucchesi, Rawls, and Maroni (1974, Nature 248: 564-67) and equal to that of each X in 2X:2A larvae according to Gvozdev, Leibovitch, and Ananiev (1983, DIS 59: 48-9). G6PD level per X-chromosome gene, as measured either by enzyme activity (Lucchesi et al.) or immunologically (Gvozdev et al.), in 3X:2A animals is two- thirds that in 2X:2A animals. other information: The term metafemale instead of superfemale was suggested by Stern (1959, Lancet 12: 1088). diploid metafemale From Bridges, 1922, Am. Nat. 56: 51-63. # haplo-4 constitution: X/X; 2/2; 3/3; 4; sex chromosome constitution may also be X/Y. source: Produced after occasional loss or nondisjunction of chromosome 4 during meiosis. Produced in quantity from crosses of C(4)RM/0 with normal or from heterozygous T(2;4) or T(3;4) females. discoverer: Bridges, 20a30. synonym: Diminished. references: 1921, Proc. Nat. Acad. Sci. USA 7: 186-92. 1922, Am. Nat. 56: 51-63 (fig.). Morgan, Bridges, and Sturtevant, 1925, Bibliog. Genet. 2: 135-43 (fig.). properties: Minute phenotype caused by deficiency for M(4). Pale body with prominent trident pattern on thorax. L5 often does not reach wing margin. Eclosion delayed 2-4 days. Via- bility erratic, usually below 80% of normal. Usually sterile. Male tends to be more viable and fertile than female. haplo-4 From Bridges, 1922, Am. Nat. 56: 51-63. # haploid constitution: X; 2; 3; 4. source: Recorded as patches of tissue. discoverer: Bridges. references: 1925, Proc. Nat. Acad. Sci. USA 11: 706-10. 1930, Science 72: 405-6. properties: Eye facets small in haploid patches. A haploid foreleg bore no sex comb; the tissue is therefore probably female, as expected on the basis of balance theory of sex determination. Gynogenetic haploid embryos are produced in crosses of normal females with homozygous ms(3)k81 males; a considerable fraction of such embryos continue development to reach the final stages of embryogenesis, producing larvae with differentiated cuticles but which never hatch (Fuyama, 1986, Genetics 112: 237-48). That haploid embryos are females is indicated by the failure of gynogenetic haploids produced by da females to develop and the failure of the androcidal spiroplasma SR, derived from Drosophila nebulosa to affect such development (Fuyama, 1987, DIS 66: 53). Nuclear divi- sion cycle of haploid embryos protracted compared to diploids, and the syncytial blastoderm nuclei undergo an extra division to produce twice the normal density prior to cellularization (Edgar, Kiehle, and Schubiger, 1986, Cell 44: 365-72). # intersex constitution: X/X; 2/2/2; 3/3/3; 4/4/4; presence of Y and number of fourth chromosomes variable. source: Regularly found among progeny of triploid females. discoverer: Bridges, 20l. references: 1921, Science 54: 252-54. 1922, Am. Nat. 56: 51-63 (fig.). Morgan, Bridges, and Sturtevant, 1925, Bibliog. Genet. 2: 153-62 (fig.). Bridges, 1939, Sex and Internal Secretions (E. Allen, C. H. Danforth, and C. A. Doisy, eds.). The Williams and Wilkins Co., pp. 15-63. properties: Large-bodied fly with coarse bristles, roughish eyes, and scalloped wing margins. Small hairs on surface of wing more sparsely distributed than in diploids. Usually has sex combs and a mixture of male and female genitalia; geni- talia may be malelike or femalelike. Flies contain a patchy distribution of male and female tissue rather than intermediate sexuality; foreleg contains male sex-comb bris- tles or female bristles or both, but not bristles of inter- mediate position and morphology as seen in dsx; abdomen may consist of a sharply delineated mosaic of male and female pig- mentation (Stern, 1968, Genetic Mosaics and Other Essays, Har- vard University Press, Cambridge). This genotype is apparently unstably situated at the point of decision in sex- ual differentiation, and the mosaic phenotype seems to be a product of alternative sexual determination. The probability of male versus female development appears to be subject to extraneous influences. For example, Fung and Gowan (1956, J. Exp. Zool. 134: 515) reported that a triploid line producing intersexes with predominantly female genitalia carried several fourth chromosomes; raising intersexes at 27-30 reported to have a feminizing effect on development (Lauge, 1969, Ann. Embryol. Morphog. 2: 245-69, 273-99). Gonads of triploid intersexes may be male like, female like or mosaic; XO- type crystals are present in spermatocytes of XXAAA but not XXYAAA intersexes; spermatocytes of the latter type can produce abnormal spermatozoa, which subsequently degenerate (Lauge, 1969, Ann. Soc. Entomol. Fr. (NS) 5: 253-514). Flies are uniformly sterile. Addition of sections of X chromosome shifts intersexes toward femaleness [Dobzhansky and Schultz, 1934, J. Genet. 28: 349-86 (fig.); Pipkin, 1940, Univ. Texas Publ. 4032: 126-56]. Addition of sections of the second or the third chromosome has not resulted in a shift of sexuality (Pipkin, 1947, Genetics 32: 592-607; 1960, Genetics 45: 1205-16). Gene activity per X chromosome in 2X;3A intermediate between that of 2X;2A or 3X;3A and 1X;2A as measured by enzyme activity in homogenates of adult flies (Faizullen and Gvozdev, 1973, Genetika 9: 106-07; Lucchesi and Rawls, 1973, Genetics 73: 459-64) and as measured by uridine incorporation by polytene chromosomes (Maroni and Plaut, 1973, Chromosoma 40: 361-77; Ananiev, Faizullen, and Gvozdev, 1974, Chromosoma 45: 193-201; Leibovitch, Belyaeva, and Zhimulev, 1976, Chro- mosoma 54: 349-62). metamale From Bridges, 1922, Am. Nat. 56: 51-63. # metamale constitution: X/Y; 2/2/2; 3/3/3; 4/4/4; inferred from markers inherited. May also be diplo-4. source: Occurs among progeny of triploid female. discoverer: Bridges, 20l. synonym: supermale. references: 1921, Science 54: 252-54. 1922, Am. Nat. 56: 51-63 (fig.). Morgan, Bridges, and Sturtevant, 1925, Bibliog. Genet. 2: 153-62 (fig.). properties: Male has small body and spread wings. Late hatch- ing, poorly viable, and completely sterile. Single polytene X of XY:3A metamale incorporates 90% as much uridine as all three X chromosomes in triploid larvae; G6PD and 6GPD levels in metamales over 80% those of triploid females (Lucchesi, Belote, and Maroni, 1977, Chromosoma 65: 1-7). # nullo-X constitution: Y/Y; 2/2; 3/3; 4/4. source: One-fourth the progeny from crosses between certain compound-X-bearing females [e.g., C(1)RM/Y] and normal males. properties: Dies as embryo (Li, 1927, Genetics 12: 1-58). Cleavage nuclei abnormally distributed and blastoderm not formed (Poulson, 1940, J. Exp. Zool. 83: 271-325). According to Scriba (1964, Zool. Jahrb. Abt. Anat. Ontog. Tiere 81: 435-90), migration of cleavage nuclei to surface of egg is normal, blastoderm formation irregular, and germ band develop- ment frequently incomplete. # nullo-X nullo-Y constitution: 2/2; 3/3; 4/4. source: One-fourth the progeny of crosses such as C(1)RM/0 females with YSX.YL/0 males. properties: Most embryos die after 10-12 cleavages (von Borstel and Rekemeyer, 1958, Nature 181: 1597-98). Embryology like that of nullo-X (Scriba, 1964, Zool. Jahrb. Abt. Anat. Ontog. Tiere 81: 435-90). # superfemale: see diploid metafemale # supermale: see metamale tetra-4 above: tetra-4; below: diplo-4 From Grell, 1961, Genetics 46: 1173-83. # tetra-4 constitution: X/X; 2/2; 3/3; 4/4/4/4. Sex chromosome constitu- tion may also be X/Y; that for chromosome 4 may be 44/4/4 or 44/44. references: Morgan, Bridges, and Sturtevant, 1925, Bibliog. Genet. 2: 135-43. Li, 1927, Genetics 12: 1-58. Bridges, 1935, Tr. Dinam. Razvit. 10: 463-74. Grell, 1961, Genetics 46: 1177-83 (fig.). Grell, 1972, DIS 48: 69. properties: Viability slightly reduced; 68-76% of diplo-4 sibs and 58-63% that of triplo-4 (Moore and Grell, 1972, Genetics 70: 567-81, 583-93). Wings of survivors longer and more pointed than normal. source: Synthesized as females homozygous for T(1;4)wm4 + T(1;4)BS formed by recombination in region 3C4-15F8 between T(1;4)wm5 = T(1;4)3C3-4;101F1-2 and T(1;4)BS = T(1;4)15F9- 16A1;16A7-B1;102F (Grell, 1961). Also recovered from progeny of crosses between males and females that carry C(4)RM (Moore and Grell). # tetraploid constitution: X/X/X/X; 2/2/2/2; 3/3/3/3; 4/4/4/4. source: Seen on a few occasions as a tetraploid daughter of a triploid female or as a patch of tetraploid gonial tissue in an otherwise diploid female. Extensive attempts to produce tetraploid males have failed. (see Novitshi, 1984, DIS 60: 157). discoverer: Bridges. references: 1925, Am. Nat. 59: 127-37. Morgan, 1925, Genetics 10: 148-78. properties: Recognized by production of progeny that are almost exclusively triploids and intersexes. # triplo-4 constitution: X/X; 2/2; 3/3; 4/4/4. Sex chromosome constitu- tion may be X/Y; that for chromosome 4 may be 44/4. source: Product of nondisjunction of chromosome 4. Regular product of cross between C(4)RM and normal diplo-4 flies. discoverer: Bridges, 21b13. references: 1922, Am. Nat. 56: 51-63. Morgan, Bridges, and Sturtevant, 1925, Bibliog. Genet. 2: 21 (fig.), 135-43. properties: Phenotypic departure from normal very slight. Body darker than normal and trident pattern subdued. Eyes small. Body and wings elongate. Preferential segregation of the dif- ferent fourth chromosomes in triplo-4's described by Stur- tevant (1936, Genetics 21: 444-66). # triploid constitution: X/X/X; 2/2/2; 3/3/3; 4/4/4. Sex chromosome con- stitution may also be X/X/X/Y, XX/X, or XX/X/Y. Triploids from stocks kept for several generations usually carry only two fourth chromosomes, i.e., diplo-4 triploids. source: Spontaneous from unreduced eggs; incidence increased by treatment with cold (Bauer, 1946, Z. Naturforsch. 1: 35-38; Gloor, 1950, DIS 24: 82) or with colchicine (Braungart and Ott, 1942, Sci. Counselor 8: 105; Schultz). Produced in relatively high frequency by triploid females and by c(3)G/c(3)G females (Gowen, 1933, J. Exp. Zool. 65: 83-106). discoverer: Bridges, 1920. references: 1921, Science 54: 252-54. 1922, Am. Nat. 56: 51-63 (fig.). Morgan, Bridges, and Sturtevant, 1925, Bibliog. Genet. 2: 135-43. properties: Eye facets larger and hairs on surface of wings more sparsely distributed than in diploid, giving eyes and wings a coarse texture; bristles also coarse. These charac- teristics are diagnostic for three sets of autosomes and result from increased cell size. Body thickset. Ventral bris- tles between first and second pairs of legs often missing. Discernible from diploid with practice. Triploid females have the same wet weight and the same amount of DNA per fly as do diploid females (Lucchesi and Rawls, 1973, Biochem. Genet. 9: 41-51); however, they have fewer and larger cells than diploids (Dobzhansky, 1929, Wilhelm Roux's Arch. Entwick- lungsmech. Org. 115: 363-79). Perhaps owing to a reduced number of neurons, triploid females show reduced mating suc- cess when competing with their diploid sisters (Novitski and Dews, 1970, DIS 45: 101). Genetic activity per X chromosome as estimated from uridine incorporation into salivary chromo- somes (Maroni and Plaut, 1973, Chromosoma 40: 361-77) or by G6PD and 6GPD activities (Lucchesi and Rawls) the same in diploid and triploid females; thus triploid cells with 50% more chromatin exhibit 50% more activity per cell, but as there are two-thirds as many cells in triploids as diploids, the activity per fly is the same in the two genotypes. Fertility poor owing to production of aneuploid classes of gametes. Because equal numbers of chromosomes tend to go to each pole during first meiotic division, euploid gametes are produced with lower-than-expected frequencies; gametes with one X and two sets of autosomes and with two X's and one set of autosomes far outnumber those with one X and one set of autosomes or two X's and two sets of autosomes (Bridges and Anderson, 1926, Genetics 10: 418-41). Triploids that carry an attached X (attached X triploids) are more fertile and pro- duce a higher proportion of triploid progeny than free X tri- ploids. Triploids are of necessity female and their progeny include metafemales, metamales, intersexes, triploid and diploid females, and diploid males. Crossing over is markedly increased in triploids; Sturtevant (1951, Proc. Nat. Acad. Sci. USA 37: 405-7) has mapped chromosome 4 in diplo-4 tri- ploids. B, Bl, Bx, Cy, D, Dfd, H, Hw, J, L2, Me, and Sb are classifiable in a single dose in triploids. Dl, G, N, bwV1, Px, S, and all Minutes are recessive in a single dose. Two doses of D, Dl, G, H, bwV1, Px, and Sb produce an extreme phenotype, whereas two doses of M or Me are lethal (Schultz, 1934, DIS 1: 55). # triploid metafemale constitution: X/X/X/X; 2/2/2; 3/3/3; 4/4/4; third 4 may be absent. source: Found among progeny of tetraploid female (Morgan). Also produced by nondisjunction of sex chromosomes in C(1)RM/In(1)sc8/Y triploid (Frost). discoverer: L. V. Morgan. references: 1925, Genetics 10: 147-78. Frost, 1960, Proc. Nat. Acad. Sci. USA 46: 47-51. properties: Coarse eyes, wing texture, and bristles. Resembles triploid except body smaller and eyes more bulging. Inner wing margins often incised. Using exceptional triploid females as a standard, Frost (1960) determined that triploid metafemales have 25% viability, 24-54% lay eggs (1 to 150 eggs), and about 11% of the eggs develop into adults. # X0 male constitution: X; 2/2; 3/3; 4/4. source: Product of primary nondisjunction of the sex chromo- somes in either father or mother in cross of X/Y male with X/X female. Forms one-fourth the progeny of crosses, such as X/X female by YSX.YL/0 male or C(1)RM/0 female by X/Y male. discoverer: Bridges. references: 1916, Genetics 1: 1-52. properties: Male morphologically normal but entirely sterile. No motile sperm produced. Spermatogenesis described by Kiefer (1966, Genetics 54: 1441-52) and by Meyer (1968, Z. Zellforsch. 84: 141-75; Genetics 61 Supplement: 79-92); the phenotype is the consequence of the simultaneous deletion of the six Y-linked fertility genes plus Su(Ste) and bb; the effects of removal of these genes one at a time have been described (Hardy, Tokuyasu, and Lindsley, 1981, Chromosoma 83: 593-617; Goldstein, Hardy, and Lindsley, 1982, Proc. Nat. Acad. Sci. USA 79: 7404-09; Hardy, Lindsley, Livak, Lewis, Sivertsen, Joslyn, Edwards, and Bonaccorsi, 1984, Genetics 107: 591-610). The phenotype includes abnormal distribution of chromosomes and mitochondrial material at meiosis 1, the presence of micronuclei in spermatids, depression of Ste on the X, and the presence of needle-shaped proteinaceous cry- stals in primary spermatocytes, spermatids, and extracellu- larly; these phenotypes are attributable to the absence of Su(Ste). Nucleoprotein structures ordinarily present in pri- mary spermatocyte nuclei attributable to Kl-5, kl-3, and ks-1 are missing. The outer dynein arms associated with the peri- pheral microtubular doublets of the axoneme are reduced or absent owing to the absence of kl-5 and kl-3, and three sperm proteins in the 300-350 kd range attributable to kl-5, kl-3 and kl-2 are missing. The combined effects of these early defects lead to the general disorganization of structure as spermiogenesis continues. The contributions of kl1, bb, and ks2 to the XO phenotype have not been sorted out, although their individual effects have been described. # XXY female constitution: X/X/Y; 2/2; 3/3; 4/4. Sex chromosome constitu- tion may also be X/XY or XX/Y. source: Product of either primary or secondary nondisjunction in either male or female. Also produced from cross of an XY- bearing parent with a normal-X-bearing parent. Condition usu- ally found in compound-X-bearing female. discoverer: Bridges. references: 1916, Genetics 1: 1-52. properties: Phenotype and fertility like those of normal female. Nondisjunction of X chromosomes in X/X/Y much higher than in X/X female; about 4% exceptions with two normal X chromosomes and much higher if X's are heterozygous for inver- sions (Sturtevant and Beadle, 1936, Genetics 21: 554-604). # XXYY female constitution: X/X/Y/Y; 2/2; 3/3; 4/4. Sex constitution may also be XX/Y/Y, X/XY/Y, or XY/XY. source: A common product of crosses such as YSX.YL/Y male by X/YSX.YL or X/X/Y female, or X/Y/Y male by XSX.YL/X, X/X/Y, or C(1)RM/Y female. discoverer: Stern. references: 1929, Biol. Zentr. 49: 261-90; 727. Cooper, 1956, Genetics 41: 242-64. properties: Eye color mottled to varying degrees. Posterior and middle legs often malformed. Fertility and viability reduced. Gametes preponderantly X/Y in constitution owing to the regular segregation of both the X's and the Y's at the first meiotic division. Sometimes sterile. # XYY male constitution: X/Y/Y; 2/2; 3/3; 4/4. Sex chromosome constitu- tion may aso be XY/Y. source: About one-fourth the progeny of crosses such as X/X/Y female by X/Y male, C(1)RM/Y female by YSX.YL/Y male, and X/YSX.YL female by X/Y male. discoverer: Bridges. references: 1916, Genetics 1: 1-52. properties: Phenotype normal; usually fertile; with certain normal Y chromosomes, completely sterile (R. F. Grell). The two Y chromosomes tend to separate at the first meiotic divi- sion to a degree depending on the source of the Y's and the X (Grell, 1958, Proc. Intern. Congr. Genet. 10th., Vol. 2: 105). # XYYY male constitution: X/Y/Y/Y; 2/2; 3/3; 4/4. Sex chromosome constitu- tion may also be XY/Y/Y. discoverer: Stern. references: 1929, Biol. Zentr. 49: 261-90. Morgan, Bridges, and Schultz, 1934, Carnegie Inst. Wash. Year Book 33: 274-80. Cooper, 1956, Genetics 41: 242-64. properties: Morphologically normal male but with mottled eyes as in XXYY female. Almost entirely sterile owing to the pres- ence of three doses of kl-3 (Kennison, 1981, Genetics 98: 529-48). Cooper (1956) suggests that the few offspring may result from X/Y/Y cysts produced by mitotic loss of a Y chromosome.