ovar {qtlbook}

Interspecific backcross in Drosophila

Description

Data on ovariole number in a backcross between D. simulans and D. sechellia; the majority of individuals were selected to be recombinant in the region of a putative QTL on chromosome 3.

Usage

ovar

Format

An object of class cross. See qtl::read.cross() for details.

Details

The data come from an interspecific Drosophila backcross. D. simulans was crossed to D. sechellia, and the F_1 hybrid was crossed back to D. simulans.

The phenotype of interest was ovariole number in females (a measure of fitness). Phenotypes on1 and on2 are the ovariole counts in the left and right gonads. The phenotype onm is the average of the two counts; for many individuals, the ovariole count for one of two gonads was missing, and so onm is missing.

In an initial cross of 402 individuals, 383 had complete phenotype data. Initial genotyping focused on 94 individuals with extreme phenotype.

To increase the resolution of a major QTL identified on chromosome 3, a second cross of approximately 7000 flies was performed, though only 1050 individuals showing a recombination event between two morphological markers, st (bright red eyes) and e (dark brown body), were phenotyped and genotyped; 1038 had complete phenotype data. The aim was to oversample recombinants of the region of the QTL.

There are genotype data for 24 markers on 3 chromosomes. (The fourth chromosome had one marker, but showed no effect and is not included in these data.)

The phenotype cross indicates whether an individual came from the first or second cross.

Alleles "I" and "E" refer to D. simulans and D. sechellia, respectively.

Source

Virginie Orgogozo, Department of Ecology and Evolutionary Biology, Princeton University, [e-mail]

References

Orgogozo, V., Broman, K. W. and Stern, D. L. (2006) High-resolution QTL mapping reveals sign epistasis controlling ovariole number between two Drosophila species. Genetics 173, 197–205.

See Also

link{gutlength}, link{iron}, link{myocard}, link{nf1}, link{trout}

Examples

data(ovar)
library(qtl)
plot(ovar)