SPERM PREFERENCE IN DROSOPHILA MELANOGASTER  †

Genetics ◽  
1972 ◽  
Vol 71 (3) ◽  
pp. 417-427
Author(s):  
D Childress ◽  
D L Hartl

Abstract A mating is described in which the females appear actively to discriminate against one of the genotypes of sperm. The males in the mating carry T(1;4)B  S  , and the sperm type selected against is the B  S+4-bearing segregant. Prior exposure of the reproductive tract of the females to B  S+4-bearing sperm seems to enhance the ability of the females to subsequently discriminate against B  S+4-bearing sperm. Thus it appears that at least some females of Drosophila melanogaster do possess a mechanism whereby different types of sperm can be distinguished—the sperm preference observed in this system appears to be independent of the meiotic drive in the T(1;4)B  S males.

Genetics ◽  
1999 ◽  
Vol 151 (2) ◽  
pp. 749-760 ◽  
Author(s):  
Armin Schmidt ◽  
Gioacchino Palumbo ◽  
Maria P Bozzetti ◽  
Patrizia Tritto ◽  
Sergio Pimpinelli ◽  
...  

Abstract The sting mutation, caused by a P element inserted into polytene region 32D, was isolated by a screen for male sterile insertions in Drosophila melanogaster. This sterility is correlated with the presence of crystals in spermatocytes and spermatids that are structurally indistinguishable from those produced in males carrying a deficiency of the Y-linked crystal (cry) locus. In addition, their morphology is needle-like in Ste+ flies and star-shaped in Ste flies, once again as observed in cry– males. The sti mutation leads to meiotic drive of the sex chromosomes, and the strength of the phenomenon is correlated with the copy number of the repetitive Ste locus. The same correlation is also true for the penetrance of the male sterile mutation. A presumptive sti null allele results in male sterility and lethal maternal effect. The gene was cloned and shown to code for a putative protein that is 866 amino acids long. A C-terminal domain of 82 amino acids is identified that is well conserved in proteins from different organisms. The gene is expressed only in the germline of both sexes. The interaction of sting with the Ste locus can also be demonstrated at the molecular level. While an unprocessed 8-kb Ste primary transcript is expressed in wild-type males, in X/Y homozygous sti males, as in X/Y cry– males, a 0.7-kb mRNA is produced.


Genetics ◽  
1972 ◽  
Vol 72 (1) ◽  
pp. 105-115
Author(s):  
George L Gabor Miklos ◽  
Armon F Yanders ◽  
W J Peacock

ABSTRACT The behaviour of two "meiotic drive" systems, Segregation-Distorter (SD) and the sex chromosome sc4sc8 has been examined in the same meiocyte. It has been found that the two systems interact in a specific way. When the distorting effects of SD and sc4sc8 are against each other, there is no detectable interaction. Each system is apparently oblivious to the presence of the other, gametes being produced according to independence expectations. However when the affected chromosomes are at the same meiotic pole an interaction occurs; the survival probability of the gamete containing both distorted chromosomal products is increased, rather than being decreased by the combined action of two systems.


Development ◽  
1988 ◽  
Vol 103 (2) ◽  
pp. 391-401 ◽  
Author(s):  
P. Simpson ◽  
M. El Messal ◽  
J. Moscoso del Prado ◽  
P. Ripoll

Clones of cells mutant for shaggy transform all hairs into bristles on the wing blade of Drosophila. Different types of bristles are formed at different locations. It is shown that, although shaggy cells are unable to make a correct decision between an epidermal cell pathway and that of a sensory bristle, they are nevertheless able to respond correctly to positional cues. A compilation of many clones led to the construction of a map of positional homologies in which all of the cells in any one area will produce the same kind of bristle. The result is a series of stripes oriented perpendicular to the anteroposterior axis of the wing and parallel to the dorsoventral axis. The significance of these stripes in relation to mechanisms of pattern formation is discussed.


1985 ◽  
Vol 46 (1) ◽  
pp. 101-105
Author(s):  
Aurora García-Dorado ◽  
Carlos López-Fanjul

SUMMARYAn experimental evaluation of Jódar & López-Fanjul's (1977) theoretical treatment of the optimum proportions to select when the numbers of males and females scored are unequal has been carried out for sternopleural bristle number in Drosophila melanogaster. Three different values of the sex-ratio (c) were considered (c = 1, 4 and 10) for the same total number of individuals scored per generation. For each c value two types of line were selected with proportions theoretically maximizing the response to be attained after 10 or 20 generations, respectively. Thus, there were six types of lines and each type was replicated sixfold. A good qualitative agreement was found between the observed and the expected rankings of the different types of selected lines at the designated generations.


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.


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