Chromosome analysis of chicken–quail F₁ hybrids.

<p>A. Giemsa-stained metaphase spread of a blastodermal cell of the chicken-quail F₁ hybrid, consisting of large-sized macrochromosomes and small-sized microchromosomes. B. Hoechst-stained chromosomes of cultured fibroblast cells from embryos of the chicken, chicken–quail hybrid, and quail, which show eight pairs of macrochromosomes and the Z and W sex chromosomes. The sizes of each pair of chromosomes differ between the chicken and quail chromosomes in the hybrid. C. Chromosome painting with macrochromosome-specific DNA probes and hybridization with the W-specific DNA repeat in fibroblast cells of the hybrids. Larger macrochromosomes with stronger hybridization signals are considered to be derived from chicken (GGA, <i>Gallus gallus</i>), and the others from quail (CJA, <i>Coturnix japonica</i>). Scale bars, 10 μm.</p>