Delprat M A, Stolar C E, Manso F C, Cladera J L
Inst. Genética, CNIA, INTA, CC25, Castelar 1712, Argentina.
Genetica. 2002 Sep;116(1):85-95. doi: 10.1023/a:1020963709795.
This report deals with the process of improving the stability of medfly, Ceratitis capitata, genetic sexing strains (GSS) based on the sw mutation on chromosome 2. This gene affects the rate of development as well as the eye colour and iridescence. The improved sexing strains were produced by mapping sw with deletions and then inducing and screening for new translocations with breakpoints close to the marker. The stability was assessed in large populations over many generations. Twenty-two new Y-2 translocations were identified and polytene chromosome analysis was performed to locate breakpoints. The translocation strains were ranked according to the distance of their breakpoints from sw. The map position of sw is region 20D on 2R. As data on the stability of the 22 strains accumulated, Cast 191 was shown to be the most promising as no recombination between sw and the male sex was found. After rearing the strain for 22 generations under semi-mass rearing conditions, with a population size of 15,000 adults and scoring 1000 flies per generation, only one such event was detected (estimated frequency = 3.1 x 10(-6)). Further tests are being carried out with this strain to assess its suitability as a genetic sexing strain for medfly Sterile insect technique (SIT).
本报告涉及基于2号染色体上的sw突变来提高地中海实蝇（Ceratitis capitata）遗传性别品系（GSS）稳定性的过程。该基因影响发育速度以及眼睛颜色和虹彩。通过用缺失定位sw，然后诱导并筛选具有靠近该标记断点的新易位来产生改良的性别品系。在许多代的大群体中评估稳定性。鉴定出22个新的Y-2易位，并进行多线染色体分析以定位断点。根据易位菌株断点与sw的距离对其进行排名。sw的图谱位置在2R的20D区域。随着22个菌株稳定性数据的积累，Cast 191被证明是最有前景的，因为在sw和雄性之间未发现重组。在半大规模饲养条件下饲养该品系22代，群体大小为15000只成虫，每代对1000只果蝇进行评分，仅检测到一次此类事件（估计频率 = 3.1×10⁻⁶）。正在对该菌株进行进一步测试，以评估其作为地中海实蝇不育昆虫技术（SIT）遗传性别品系的适用性。
