Compared to their sex-chromosomal regions, T. muenninki neo-sex chromosomes without distinct chromosome rearrangement are in a very early stage of sex-chromosome differentiation.
Whole chromosome changes were assigned to chromosomes without identified breakpoints if a chromosomal segment mapped to a gain or a loss level.
We anchored these contigs to seven pseudo chromosomes without the use of maps.
When C. elegans embryos inherit some chromosomes with and some chromosomes without H3K27me3, PRC2 maintains inherited states by (1) restoring levels of H3K27me3 on H3K27me3 chromosomes after DNA replication and (2) failing to de novo methylate H3K27me3 chromosomes12.
In chromosomes without inversions, there were characteristic density gradients for genes, repetitive DNA and methylation (with gene densities increasing and densities of repetitive DNA and methylation decreasing toward chromosome ends).
These findings suggest that parts of the photosynthesis-related nuclear genes in P. cutis were omitted from the chromosomes without gene rearrangement similar to the plastid genome during the shift from the photosynthetic to the heterotrophic lifestyle.
The specific growth rates of yeast strains carrying more than 16 chromosomes up to 21 did not differ significantly, suggesting that yeast cells can harbor more chromosomes than they do in their natural state, that is, 16 chromosomes, without serious effects on their growth.
In contrast, reduplicating chromosomes without separation frequently produces polytene chromosomes, a barrier to accurate mitosis.
Analysis of null chromosomes, i.e., chromosomes without genes, did not reveal significant increases in type I error.
It cannot be explained by the presence of sex chromosomes without assuming multiple independent loci for sex determination in S. viminalis (Alström-Rapaport et al., 1997).
Alternatively, if the two Holliday junctions are cut on the crossing strands (along the horizontal purple arrowheads at both Holliday junctions in Figure 4), then chromosomes without crossover will be produced.
