PREFERENTIAL SEGREGATIONS IN TRIPLOID FEMALES

Preferential Segregation in Triplo-IV Females of Drosophila Melanogaster.

H E occurrence of non-random segregation in triplo-IV females of T Drosophila melanogaster was reported in a preliminary note (STURTEVANT 1934) of which this is the full account. As there shown, and elaborated below, all the tested fourth chromosomes may be arranged in a series, of such a nature that each chromosome will (in a triplo-IV female) pass to the haplo-IV pole a t meiosis more often t...

A map of the fourth chromosome of Drosophila melanogaster, based on crossing over in triploid females.

Under ordinary conditions there is so little crossing over in the fourth chromosome of Drosophila melanogaster that the usual method of constructing a map is not practicable. Deduction from the behavior of translocations has been utilized, but as will be shown here, has led to an incorrect result. Bridges and Brehme (1944) give the seriation bt (bent), sv (shaven), ci (cubitus interruptus), gvl...

Segregations in clusters of galaxies

We analyse a sample of about 2000 galaxies in 40 regular clusters, to look for evidence of segregation with respect to galaxy luminosities and morphological types. We find evidence of luminosity segregation for galaxies brighter than MR < −21.5, i.e. typically the four brightest members of each cluster. We also find evidence of morphological segregation: both the core-radius and the velocity di...

Discovering planar segregations

Simultaneous formation of haploid, diploid and triploid eggs in diploid-triploid mosaic loaches