Ranganath H A, Hägele K
Chromosoma. 1982;85(1):83-92. doi: 10.1007/BF00344595.
Heterochromatin distribution and differentiation in metaphase chromosomes of two morphologically identical Drosophila races, D. nasuta nasuta and D. n. albomicana, have been studied by C- and N-banding methods. -- The total heterochromatin values differ only slightly between these races. However, homologous chromosomes of the two Drosophila forms show striking differences in the size of heterochromatin regions and there is an alternating pattern in D. n. nasuta and D. n. albomicana of chromosomes which contain more, or respectively less heterochromatin than their counterparts in the other race. -- Three different N-banding patterns could be obtained depending on the conditions of the method employed: One banding pattern occurs which corresponds to the C-banding pattern. Another pattern is the reverse of the C-band pattern; the euchromatic chromosome regions and the centromeres are stained whereas the pericentric heterochromatin regions remain unstained. In the Y chromosomes of both races and in chromosome 4 of D. n. albomicana, however, the heterochromatin is further differentiated. In the third N-banding pattern only the centromeres are deeply stained. Furthermore, between the races, subtle staining differences in the pericentric heterochromatin regions can be observed as verified in F1 hybrids. On the basis of C- and N-banding results specific aspects of chromosomal differences between D. n. nasuta and D. n. albomicana are discussed.
利用C带和N带技术，对两种形态相同的果蝇品种——纳苏塔果蝇指名亚种（D. nasuta nasuta）和纳苏塔果蝇白变种（D. n. albomicana）中期染色体的异染色质分布及分化情况进行了研究。——这两个品种的总异染色质值仅略有差异。然而，这两种果蝇形态的同源染色体在异染色质区域大小上存在显著差异，在纳苏塔果蝇指名亚种和纳苏塔果蝇白变种中，染色体的异染色质含量相较于另一品种的对应染色体，呈现出一种交替模式，即有的染色体含有更多异染色质，而有的则较少。——根据所采用方法的条件，可以获得三种不同的N带模式：一种带型模式与C带模式相对应。另一种模式与C带模式相反；常染色体区域和着丝粒被染色，而着丝粒周围的异染色质区域未被染色。然而，在两个品种的Y染色体以及纳苏塔果蝇白变种的第4号染色体中，异染色质进一步分化。在第三种N带模式中，只有着丝粒被深染。此外，在两个品种之间，可以观察到着丝粒周围异染色质区域存在细微的染色差异，这在F1杂种中得到了验证。基于C带和N带的结果，讨论了纳苏塔果蝇指名亚种和纳苏塔果蝇白变种之间染色体差异的具体方面。
