After 2—3 min of acclimation time, the number of times the male crossed the center line within the 3-min observation time was counted. Steps in the evolution of heteromorphic sex chromosomes. Free to read. Comparison of simultaneous hybridizations performed on sections from males and females revealed that fat-body expression was male specific, but that expression in the antennae was not.
DNA sequencing was performed by the M. Fluorescence crossing points C t were calculated with the second derivative maximum method using the LightCycler 1. Another possibility to consider is that recombination patterns may differ between sexes heterochiasmy in some species so that the X and Y chromosomes may not recombine simply because males do not recombine whereas females do [ 15 ].
In principle, conflict resolution may be achieved by sex chromosomes and sex determination pptx in Chandler balanced sex ratios at the parental level through selection of females producing balanced sex ratios [ 49 ]. The observation that, in addition to sex and nutrition, takeout also responds to circadian rhythms Sarov-Blat et al.
BioStudies: supplemental material and supporting data. Reasoning from Drosophila.
The results from three different transgenic takeout—GAL4 lines are shown lines 1,2,3. Animals The broodstock for the M. We conclude that the X and Y chromosomes of A. However, the existence of YY individuals and XY females implies that the standard expectation of sex chromosome N e does not apply to A.
Interestingly, this situation restores balanced sex ratios at the population level, as indicated by our simulations Fig 4 and consistent with empirical evidence [ 3548 ]. Hybridization to the takeout probe was absent in takeout to 1 males. X-gal staining was done as described by Fischer and Maniatis
Wolbachia frequency in progenies was calculated as the Wolbachia frequency observed among tested females weighted by female proportion in the progenies as all males lack Wolbachia. This situation challenges the classical model of sex chromosome evolution by affecting sex chromosome effective population size N e and recombination patterns.
Simulation of sex chromosome frequencies To evaluate the evolutionary impact of cytoplasmic sex ratio distorters on sex chromosome frequencies, we extended Taylor's theoretical work [ 31 ] to enable the transmission rate of the distorter to vary according to female sex chromosome genotypes.
By contrast, Wolbachia infected none of the offspring of the 4 YY mothers.