CORRIGENDUM

Cytogenetic Analysis of the Third Chromosome Heterochromatin of Drosophila melanogaster

In the article by DMITRY E. KORYAKOV, IGOR F. ZHIMULEV and PATRIZIO DIMITRI (Genetics 160: 509–517) entitled "Cytogenetic Analysis of the Third Chromosome Heterochromatin of Drosophila melanogaster," on page 516, first column, line 10, the sentence should be replaced with the following text:

The D. melanogaster genome consists of 180 Mb of DNA and contains 14000 euchromatic genes (ADAMS et al. 2000). Euchromatin consists of 120 Mb, while the remaining 60 Mb corresponds to heterochromatin with the heterochromatic portions of chromosomes 2 and 3 accounting for about 20 Mb. It follows that 1 Mb of euchromatin contains on average 120 genes (14000/120), while only 1.4 genes (28/20) per 1 Mb of heterochromatin of chromosomes 2 and 3 are found. Thus, the density of genes in heterochromatin is about 1% of that in euchromatin.