A. V. Rodionov and M. S. Chechik Russian Journal of Genetics. 2002. V. 38, N.9 P. 1054 - 1059.
Lampbrush Chromosomes in the Japanese Quail Coturnix coturnix japonica: Cytological Map of Macrochromosomes and Meiotic Crossing-over Frequency in Females.
Russian Journal of Genetics. 2002. V. 38, N.9 P. 1054 - 1059.

Cytological map of lampbrush macrobivalents of the Japanese quail (Coturnix coturnix japonica) were constructed. Investigation of chiasmata allowed to estimate the frequency of reciprocal genetic recombi- nation (crossing over) in Japanese quail female meiosis. The total chiasma number in bivalents of Japanese quail oocyte nuclei was determined to be 53–58. Macrobivalents 1–5 and Z of the Japanese quail had on average 3.3 chiasmata per bivalent, and microbivalents, 1.0–1.1 chiasmata per bivalent. The chiasmata (crossover) frequency in Japanese quail females was lower than in chicken. In macrochromosomes of Japanese quail females, one crossover occurred per 43.9 Mb, and in chicken, per 30.0 Mb. Judging from chiasma frequency, the genetic length of the Japanese quail genome is likely to be 2650–2900 cM. Crossover frequency in the species was 0.023 per Mb in macrobivalents and 0.07–0.08 Mb in microbivalents and for the total genome, 0.041 crossing over per Mb. The genetic length of one Mb (recombination rate θ) in female Japanese quails was 1.14 cM in macrochromosomes, 3.60–4.12 cM in microchromosomes, and about 1.96–2.15 cM averaged over the genome.