scholarly journals DoesStellateCause Meiotic Drive inDrosophila melanogaster?

Genetics ◽  
2002 ◽  
Vol 161 (4) ◽  
pp. 1551-1559 ◽  
Author(s):  
Massimo Belloni ◽  
Patrizia Tritto ◽  
Maria Pia Bozzetti ◽  
Gioacchino Palumbo ◽  
Leonard G Robbins

AbstractDrosophila melanogaster males deficient for the crystal (cry) locus of the Y chromosome that carry between 15 and 60 copies of the X-linked Stellate (Ste) gene are semisterile, have elevated levels of nondisjunction, produce distorted sperm genotype ratios (meiotic drive), and evince hyperactive transcription of Ste in the testes. Ste seems to be the active element in this system, and it has been proposed that the ancestral Ste gene was “selfish” and increased in frequency because it caused meiotic drive. This hypothetical evolutionary history is based on the idea that Ste overexpression, and not the lack of cry, causes the meiotic drive of cry– males. To test whether this is true, we have constructed a Ste-deleted X chromosome and examined the phenotype of Ste–/cry– males. If hyperactivity of Ste were necessary for the transmission defects seen in cry– males, cry– males completely deficient for Ste would be normal. Although it is impossible to construct a completely Ste– genotype, we find that Ste–/cry– males have exactly the same phenotype as Ste+/cry– males. The deletion of all X chromosome Ste copies not only does not eliminate meiotic drive and nondisjunction, but it also does not even reduce them below the levels produced when the X carries 15 copies of Ste.

Genetics ◽  
1989 ◽  
Vol 122 (1) ◽  
pp. 81-86 ◽  
Author(s):  
E S Walker ◽  
T W Lyttle ◽  
J C Lucchesi

Abstract In order to test whether the meiotic drive system Segregation distorter (SD) can operate on the X chromosome to exclude it from functional sperm, we have transposed the Responder locus (Rsp) to this element. This was accomplished by inducing detachments of a compound-X chromosome in females carrying a Y chromosome bearing a Rsps allele. Six Responder-sensitive-bearing X chromosomes, with kappa values ranging from 0.90 to 1.00, were established as permanent lines. Two of these have been characterized more extensively with respect to various parameters affecting meiotic drive. SD males with a Responder-sensitive X chromosome produce almost exclusively male embryos, while those with a Rsp-Y chromosome produce almost exclusively female embryos. This provides a genetic system of great potential utility for the study of early sex-specific differentiation events as it allows the collection of large numbers of embryos of a given sex.


Genetics ◽  
1987 ◽  
Vol 116 (3) ◽  
pp. 409-413
Author(s):  
Bruce McKee

ABSTRACT Males carrying certain X-4 translocations exhibit strongly skewed sperm recovery ratios. The XP4D half of the translocation disjoins regularly from the Y chromosome and the 4PXD half disjoins regularly from the normal 4. Yet the smaller member of each bivalent is recovered in excess of its pairing partner, apparently due to differential gametic lethality. Chromosome recovery probabilities are multiplicative; the viability of each genotype is the product of the recovery probability of its component chromosomes. Meiotic drive can also be caused by deficiency for X heterochromatin. In(1)sc4Lsc8R males show the same size dependent chromosome recoveries and multiplicative recovery probabilities found in T(1;4)BS males. Meiotic drive in In(1)sc4Lsc8R males has been shown to be due to X-Y pairing failure. Although pairing is regular in the T(X;4) males, the striking phenotypic parallels suggest a common explanation. The experiments described below show that the two phenomena are, in fact, one and the same. X-4 translocations are shown to have the same effect on recovery of independently assorting chromosomes as does In(1)sc4Lsc8R. Addition of pairing sites to the 4PXD half of the translocation eliminates drive. A common explanation—failure of the distal euchromatic portion of the X chromosome to participate in X:Y meiotic pairing—is suggested as the cause for drive. The effect of X chromosome breakpoint on X-4 translocation induced meiotic drive is investigated. It is found that translocations with breakpoints distal to 13C on the salivary map do not cause drive while translocations broken proximal to 13C cause drive. The level of drive is related to the position of the breakpoint—the more proximal the breakpoint the greater the drive.


Genetics ◽  
1981 ◽  
Vol 98 (3) ◽  
pp. 529-548
Author(s):  
James A Kennison

ABSTRACT Cytological and genetic analyses of 121 translocations between the Y chromosome and the centric heterochromatin of the X chromosome have been used to define and localize six regions on the Y chromosome of Drosophila melanogaster necessary for male fertility. These regions are associated with nonfluorescent blocks of the Y chromosome, as revealed using Hoechst 33258 or quinacrine staining. Each region appears to contain but one functional unit, as defined by failure of complementation among translocations with breakpoints within the same block. The distribution of translocation breakpoints examined appears to be nonrandom, in that breaks occur preferentially in the nonfluorescent blocks and not in the large fluorescent blocks.


Genetics ◽  
1987 ◽  
Vol 115 (1) ◽  
pp. 143-151
Author(s):  
Andrew G Clark

ABSTRACT Functional variation among Y chromosomes in natural populations of Drosophila melanogaster was assayed by a segregation study. A total of 36 Y chromosomes was extracted and ten generations of replacement backcrossing yielded stocks with Y chromosomes in two different genetic backgrounds. Eleven of the Y chromosomes were from diverse geographic origins, and the remaining 25 were from locally captured flies. Segregation of sexes in adult offspring was scored for the four possible crosses among the two backgrounds with each Y chromosome. Although the design confounds meiotic drive and effects on viability, statistical partitioning of these effects reveals significant variation among lines in Y chromosome segregation. Results are discussed in regards to models of Y-linked segregation and viability effects, which suggest that Y-linked adaptive polymorphism is unlikely.


Genetics ◽  
1990 ◽  
Vol 125 (1) ◽  
pp. 51-76
Author(s):  
K G Golic

Abstract Segregation distortion in Drosophila melanogaster is the result of an interaction between the genetic elements Sd, a Rsp sensitive to Sd, and an array of modifiers, that results in the death of sperm carrying Rsp. A stock (designated M-5; cn bw) has been constructed which has the property of inducing the partial loss of sensitivity from previously sensitive cn bw chromosomes, the partial loss of distorting ability from SD chromosomes, and a concomitant acquisition of modifiers on the X chromosome and possibly also on the autosomes. By several criteria the changes exhibited under the influence of M-5; cn bw are characteristic of the transposable-element systems which produce hybrid dysgenesis. In the first place, the magnitude of these effects depends on the nature of the crosses performed. The analogy is further strengthened by the observation that the changes induced by M-5; cn bw share other stigmata of Drosophila transposable-element systems, including high sterility among the progeny of outcrosses, and the production of chromosomal rearrangements. The possible relationship of this system to the P, I and hobo transposable element systems is discussed, as well as its bearing on aspects of the Segregation Distorter phenomenon which have yet to be explained.


Genetics ◽  
1983 ◽  
Vol 103 (2) ◽  
pp. 219-234
Author(s):  
James A Kennison

ABSTRACT The frequencies of newly induced male-sterilizing lesions on both the X and Y chromosomes of Drosophila melanogaster were determined after either 4000 r of γ-irradiation or adult feeding of ethyl methanesulfonate. The Y chromosome is approximately twice as sensitive as the X chromosome to newly induced male-sterilizing lesions after γ-irradiation, but slightly less sensitive after ethyl methanesulfonate treatment. A large proportion of the radiation-induced lesions are associated with Y-autosome or X-autosome translocations, with the Y chromosome recovered in translocations far in excess of the frequency expected from metaphase lengths. Although translocations between the X and Y chromosomes or between autosomes do not appear to sterilize heterozygous males, interchanges between sex chromosomes and autosomes often sterilize males carrying them in a dominant manner, suggesting that the organization of the genome is critical for normal spermatogenesis. Complementation tests between recessive Y-linked male-sterilizing mutants do not reveal the existence of any additional fertility loci beyond the six previously defined.


Genetics ◽  
1976 ◽  
Vol 82 (1) ◽  
pp. 25-34
Author(s):  
W Kunz

ABSTRACT The number of rRNA cistrons is measured by filter saturation hybridization in different stocks of D. hydei, where the wild-type X chromosome has one nucleolus organizer (NO) and the wild-type Y has two separated NO's. (see PDF) females having no X chromosomal NO show an rDNA content exceeding that of a Y chromosome. An even greater increase in the rRNA cistron number is measured in two translocation stocks where the (see PDF) is combined with one half of a Y and, therefore, each stock contains only one of the two Y chromosomal NO's. But when the same Y fragments are brought together with a wild-type X chromosome they lose about one-half of their rRNA cistrons within one generation. Males with two complementary Y fragments but having no X chromosomal NO show a considerably higher rDNA content than the (see PDF) females, although both are equal in respect of their NO number. Consideration is given to related phenomena in Drosophila melanogaster.


Genetics ◽  
1992 ◽  
Vol 132 (4) ◽  
pp. 1033-1037 ◽  
Author(s):  
Y Y Shevelyov

Abstract Two variants of X chromosome Stellate genes responsible for crystal formation in XO male primary spermatocytes occupy different genome positions. The majority if not all of the 1250-bp Stellate genes are located at the 12E site where the Ste locus has been mapped and almost all of the 1150-bp Stellate repeats are concentrated in the distal X heterochromatin. Sequencing of Stellate genes derived from X heterochromatin reveals the preservation of their open reading frames and precise matching with some Stellate cDNAs reported earlier. At least some heterochromatic Stellate genes are suggested to be expressed and, therefore, involved in the interaction with the Y chromosome locus Su(Ste), as are the Stellate genes from 12E.


Genetics ◽  
1989 ◽  
Vol 121 (4) ◽  
pp. 751-763 ◽  
Author(s):  
T W Lyttle

Abstract In the Segregation distorter (SD) system of meiotic drive, a minimum of two trans-acting elements [Sd and E(SD)] act in concert to cause a certain probability of dysfunction for sperm carrying a sensitive allele at the Responder (Rsp) target locus. By employing a number of insertional translocations of autosomal material into the long arm of the Y chromosome, Rsp can be mapped as the most proximal locus in the 2R heterochromatin as defined both by cytology and lethal complementation tests. Several of these insertional translocations result in the transposition of Rsp to the Y chromosome, where its sensitivity remains virtually unaltered. This argues that Rsp is separable from the second chromosome centromere, that its behavior does not depend on its gross chromosomal position, and that meiotic pairing of the chromosomes carrying the various SD elements is not a prerequisite for sperm dysfunction. Several other translocations apparently leave both resulting chromosomes at least partially sensitive to SD action, suggesting that Rsp is a large subdivisible genetic element. This view is compatible with observations published elsewhere that suggest that Rsp is a cytologically large region of highly repetitive AT-rich DNA. The availability of Y-linked copies of Rsp also allows the construction of SD males carrying two independently segregating Rsp alleles; this in turn allows the production of sperm with zero, one or two Rsp copies from the same male. Examination of the relative recovery proportions of progeny arising from these gametes suggests that sperm with two Rsp copies survive at much lower frequencies than would be predicted if each Rsp acted independently in causing sperm dysfunction. Possible explanations for such behavior are discussed.


Genetics ◽  
1972 ◽  
Vol 71 (4) ◽  
pp. 597-606
Author(s):  
Robert A Voelker

ABSTRACT In D. affinis "sex ratio" (sr), a form of meiotic drive characterized by the production of mostly or only female progeny by certain males, is associated with two different X chromosome sequences, XS-I XL-II and XS-II XL-IV. The behavior of the two sequences differed, depending on the Y chromosome constitution, being either Y  L or 0. Males with sequence XS-II XL-IV and Y  L produced progenies with nearly normal sex ratios; males with the same X chromosome sequence but in the absence of a Y chromosome in some cases gave progenies with nearly normal sex ratios but in other cases gave progenies which tended toward phenotypic sr. Males with sequence XS-I XL-II and Y  L gave progenies which were characteristically sr (0.97–0.98 females); in the absence of a Y chromosome males with this sequence produced progenies which were virtually all-male. This latter finding is presumably identical to Novitski's (1947) "male sex ratio" (msr). The interpretation offered here attributes msr to an interaction between sr sequence XS-I XL-II and the 0 condition. A general consideration of the available data on sr in D. affinis is presented.


Sign in / Sign up

Export Citation Format

Share Document