Related Experiment Video
Updated: Oct 17, 2026

Manipulation of Ploidy in Caenorhabditis elegans
Published on: March 15, 2018
Chromosomal arrangement of the two main rDNA size classes of Ascaris lumbricoides
Abstract:
The two main rDNA size classes of 8.8 kb and 8.4 kb length from Ascaris lumbricoides, which comprise more than 95% of the total nuclear rDNA, are arranged as internally homogeneous clusters and are not intermingled with each other. The rRNA genes are present on a single autosomal locus as could be demonstrated by in situ hybridization of fluorochrome-labelled 18S and 26S rRNA to metaphase chromosomes of spermatocytes I. The quantitative ratio of the two rDNA size classes varies largely between individuals being on the average roughly 10:1 in the investigated wild population of A. lumbricoides. However, there are no differences in the hybridization pattern of the two rDNAs in the DNA eliminating nematode A. lumbricoides between germ line and somatic cells in any of the individuals that have been analyzed.
Related Concept Videos
Karyotyping
Lampbrush Chromosomes
LBCs are made up of two pairs of conjugating homologous chromatids. Each chromatid consists of alternatively positioned regions of condensed-inactive chromatin and loosely placed-active side loops, which can be contracted and extended. The loops resemble the...
Polytene Chromosomes
Dosage Compensation
In addition to sexual development, the X chromosome has genes involved in autosomal functions such as brain development and the immune system. Therefore, males and females with distinct numbers of X chromosomes will have...
Genetic Material

