Chelysheva L.A., Solovei I.V., Rodionov A.V., Yakovlev A.F., Gaginskaya E.R.
The lampbrush chromosomes of the chicken. The cytological map of macrobivalents.
Tsitologiia — 1990. — V. 32, — P. 303–316.

The lampbrush chromosomes (LBC) were prepared from growing oocytes of 0.75–1.50 mm in diameter. A map of six autosomes and the ZW sex bivalent is presented. Several types of landmarks were designed: lumpy loops (LL), telomeric bow–like loops (TBL), some large loops in interstitial regions (marker loops — ML). Supposedly, the centromeres of LBC in the chicken are at one of the axial bars bearing no loops. The landmarks PBL and DBL mark the proximal and distal boundaries of the bars. LBC–A (probably, chromosome 1 of the chicken karyotype) is about 185 Ám. There are 7.3▒0.2 chiasmata. Chiasmata are distributed at quasi–random. In LBC-A one chiasma is localized in a telomere, as a rule. Coordinates of 13 of the 14 different landmarks in LBC–A have been estimated. LBC–B (probably, chromosome 2) is about 151 Ám, there are 5.50▒0.23 chiasmata. The LBC–B may be identified by LL–21 and LL–22. LBC–C (probably, chromosome 3) is 128 Ám; there are 4.70▒0.18 chiasmata. The chromosome can be identified by characteristic loops LL–31, an unlooped chromomere bar near the telomere (T–32), a characteristic distribution of normal loops along LBC-C: about one half of this LBC bears large loops, and the other one — small loops. LBC–D (chromosome 4?) is 107 Ám: there are 3.80▒0.31 chiasmata. Double loop bridges appear frequently near ML-41. LBC–E (chromosome 5?) is about 72 Ám with 2.50▒0.28 chiasmata. There are characteristic TBL loops with abundant RNP material thus being like LL-loops. LBC–F (chromosome 8?) is about 36.5 Ám; there are 2 chiasmata. This LBC can be identified by giant telomeric loops GML–F1 and by unlooped bar in the middle of LBC.

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