Abstract.-Incipient sexual isolation between genotypes, lines, or populations of the same species is commonly measured in Drosophila by choice tests. Results of these tests are known to be influenced, in an undetermined manner, by the mating propensity of competitors and by discriminatory factors during courtship. We have approached the problem by measuring male and female propensities in separate, independent tests, and by examining whether these estimates could explain the results of the choice tests. First, male and female choice tests were used to measure sexual isolation between populations of Drosophila melanogaster and between populations of D. simulans. Significant deviations from random mating occurred in 31 out of 48 tests, in agreement with the propensity values of the tested genotypes. We conclude that mating propensity instead of discrimination is directly involved in the estimation of sexual isolation in our populations, and advise against the application of male and female choice tests to assess intraspecific isolation without a proper knowledge of the mating propensities of competing individuals. Second, multiple choice tests were used to assess isolation between D. melanogaster populations. In examining the dynamics of matings throughout the test, we show that if competing individuals differ in mating propensities and tests are long enough to allow most matings to happen, a spurious sexual isolation can appear. We recommend that multiple choice tests be terminated once 50 percent of matings had been observed.Key words.-Drosophila, mating choice tests, mating propensity, sexual isolation.Received March 10, 1997.The role of sexual isolation in species formation is one of the most interesting questions in evolutionary biology. Sexual isolation is a form of reproductive isolation arising from behavioral differences between potential mates. The elaborate courtship of most Drosophila species provides good material for the study of sexual behavior. Since Sturtevant's (1915) pioneering work, students of Drosophila have tried to understand how mating differences and sexual selection could lead to speciation.At the intraspecific level, incipient sexual isolation can be seen as a tendency to mate homogamically rather than heterogamically. The underlying divergence in mating behavior between two conspecific strains can be studied in different ways. Unfortunately, a direct analysis of behavioral differences is laborious, time-consuming, and requires a lot of practice and experience (Spiess 1970;Burnet and Connolly 1981;Cobb et al. 1985Cobb et al. , 1986. As a result, the most commonly used designs for measuring sexual isolation in Drosophila are the male choice, female choice, and multiple choice tests (see Parsons 1973), which measure the frequencies of intra-and interstrain matings. The male choice test consists on introducing a male from one strain with a female from his own strain and a female from another strain, in a mating chamber, and recording the types of mating that occur. In the female choice tes...
Drosophila simulans and D. melanogaster are sibling cosmopolitan species with imperfect ethological isolation. Hybridization is easy between D. melanogaster females and D. simulans males, but the reciprocal cross has been traditionally considered as very scarce and little is known about the environmental and genetic factors that affect it. We used classical genetic analyses to determine the influence of each major chromosome on the breakdown of sexual isolation between females of D. simulans and D. melanogaster males. In addition, we have made a first attempt to locate the genetic systems involved in this process. At least two genes, or two groups of genes, are responsible for hybridization, located in the X chromosome and in the left arm of chromosome II. The inheritance mode of both genetic systems is different. The genes in the X chromosome show dominance for high levels of hybridization, whereas those in chromosome II show dominance for low levels. These results contrast with other investigations on the melanogaster subgroup, suggesting independent evolutionary events during the speciation process in each species.
In total, 17 pediatric patients with hematologic malignancies (n ¼ 14) and Fanconi anemia (FA) (n ¼ 3) underwent haploidentical SCT with T-cell depletion. The patients were conditioned with reduced-intensity regimens, and CYA was used for GVHD prophylaxis. Successful engraftment occurred in 16 patients (94%). One patient failed to achieve a primary engraftment. Another patient rejected the first SCT after 10 weeks and had a successful second transplant. Of all engrafted patients, only one developed severe acute GVHD. Ten patients were alive at a median follow-up of 18 months (range, 5-62 months). The 5-years' OS was 53.8%. The three patients with FA are currently well with full-donor chimerism at 16, 6 and 5 months post transplant, respectively. The OS of 14 patients with high-risk hematologic malignancies was 47.6%. Three patients died as a result of post transplant leukemia relapse. CMV infection, GVHD and organ injury were other causes of mortality. Haploidentical SCT was found to be an alternative feasible treatment in Uruguay for patients who need allogenic transplantation but lack an HLA-identical family donor. It should be considered as an early option in FA patients before transformation or significant exposure to blood products.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.