A cell synchronization technique allowed the high-resolution GTG-banding pattern of rabbit chromosomes to be determined. A karyotype of the late-prophase 622-band stage is presented.

No abstract

A new synthetic medium (referred to as GC3) that supports the growth of the Chinese hamster ovary cell line has been developed. It is composed of a 1:1 mixture of Ham's F12 and modified Eagle's minimum essential (MEM.S) mediums supplemented with transferrin (10 micrograms/ml), insulin (80 mU/ml), and selenium (1 X 10(-7) M). Other more simple supplementations of our basal medium MEM.S/F12 (transferrin + insulin, transferrin + selenium, ferrous iron + selenium) also give good cell growth responses. Fibronectin or serum pretreatment is not needed for cellular attachment and spreading. Our culture system is characterized by a continuous serum-free cultivation (more than 200 doublings), a clonal growth, a high density proliferation, and a rapid growth rate near that of cells in serum-supplemented medium.

Using as a probe pig genomic DNA, including the complete interferon α gene, we have mapped the leukocyte interferon gene on pig chromosome 1 by in situ hybridization. A total of 196 silver grains were noted on the 106 metaphases scored: 31% of the grains were observed on chromosome 1, and 67% of these were localized in the region 1q2.2→q2.7.

RésuméL'analyse par électrophorèse de clones cellulaires hybrides interspécifiques porc-hamster chinois nous a permis de démontrer que les gènes MPI, PKM2, NP sont synténiques chez le porc (G ELUN et al., 1981). Le