Nat Rev Genet. Braasch I. Subsequent linkage mapping in homozygous parent families disclosed the structure of the inversions, while linkage mapping in families from heterozygous parents documented almost complete repression of recombination across the rearrangements Extended Data Fig.
By contrast, the macro- and microchromosomes of turtles are counterparts of those of chicken, which suggests that the ancestral karyotype of Archosauromorpha, probably composed of at least eight pairs of macrochromosomes and many indistinguishable microchromosomes, has been highly conserved for more than million years following their divergence from Lepidosauromorpha [ 24, ].
Comparison of the chicken and turkey genomes reveals a higher rate of nucleotide divergence on microchromosomes than macrochromosomes. One emerging hypothesis is that a variety of chromosomal rearrangements are mediated through the transposition of interspersed repeats, such as transposable elements TEsand expansion of tandemly organized satellite sequences, which act as catalysts to drive genome evolution [ 2021262936383940414243444546 ].
Peichel C, et al. In particular, the neo-Y chromosome of D. It contains only about 20 genes, most of which transposons drive sex chromosome evolution theory in Round Rock for male-specific functions such as sperm motility 353760 While humans and chimpanzee contain a substantial amount of ampliconic DNA, this sequence feature is almost absent from rhesus and the euchromatic segment of the MSY is notably smaller in rhesus compared to that of the human and chimpanzee; only 0.
This supports the hitchhiking model of Y chromosome degeneration see Box 4i. Both the primate and the Drosophila Y chromosome have lost most of their ancestral genes that were initially present on the autosome that formed the Y millions of years ago, and most of the remaining genes, have a male-specific function.
Short paired-end libraries with approximately bp insert sizes were sequenced with the Illumina HiSeq technology S1 Table. Patterns of microchromosome organization remain highly conserved throughout avian evolution. Their karyotypes can be categorized into two groups, consisting of those with few or no dot-shaped microchromosomes with an undetectable centromere, as found in Lacertidae and Gekkota, and those with macrochromosomes and many microchromosomes, as commonly observed in Scincoidea skinks and Episquamata iguania, snakes, and monitor lizards excluding Lacertidae [ 14 , 15 , 16 , 17 , 18 , 19 , 20 , 21 ].