TY - JOUR
T1 - The Evolution of Widespread Recombination Suppression on the Dwarf Hamster (Phodopus) X Chromosome
AU - Moore, Emily C.
AU - Thomas, Gregg W.C.
AU - Mortimer, Sebastian
AU - Kopania, Emily E.K.
AU - Hunnicutt, Kelsie E.
AU - Clare-Salzler, Zachary J.
AU - Larson, Erica L.
AU - Good, Jeffrey M.
N1 - Publisher Copyright:
© 2022 Oxford University Press. All rights reserved.
PY - 2022/6/1
Y1 - 2022/6/1
N2 - The X chromosome of therian mammals shows strong conservation among distantly related species, limiting insights into the distinct selective processes that have shaped sex chromosome evolution. We constructed a chromosome-scale de novo genome assembly for the Siberian dwarf hamster (Phodopus sungorus), a species reported to show extensive recombination suppression across an entire arm of the X chromosome. Combining a physical genome assembly based on shotgun and longrange proximity ligation sequencing with a dense genetic map, we detected widespread suppression of female recombination across _65% of the Phodopus X chromosome. This region of suppressed recombination likely corresponds to the Xp arm, which has previously been shown to be highly heterochromatic. Using additional sequencing data from two closely related species (P. campbelli and P. roborovskii), we show that recombination suppression on Xp appears to be independent of major structural rearrangements. The suppressed Xp arm was enriched for several transposable element families and deenriched for genes primarily expressed in placenta, but otherwise showed similar gene densities, expression patterns, and rates of molecular evolution when compared to the recombinant Xq arm. Phodopus Xp gene content and order was also broadly conserved relative to the more distantly related rat X chromosome. These data suggest that widespread suppression of recombination has likely evolved through the transient induction of facultative heterochromatin on the Phodopus Xp arm without major changes in chromosome structure or genetic content. Thus, substantial changes in the recombination landscape have so far had relatively subtle influences on patterns of X-linked molecular evolution in these species.
AB - The X chromosome of therian mammals shows strong conservation among distantly related species, limiting insights into the distinct selective processes that have shaped sex chromosome evolution. We constructed a chromosome-scale de novo genome assembly for the Siberian dwarf hamster (Phodopus sungorus), a species reported to show extensive recombination suppression across an entire arm of the X chromosome. Combining a physical genome assembly based on shotgun and longrange proximity ligation sequencing with a dense genetic map, we detected widespread suppression of female recombination across _65% of the Phodopus X chromosome. This region of suppressed recombination likely corresponds to the Xp arm, which has previously been shown to be highly heterochromatic. Using additional sequencing data from two closely related species (P. campbelli and P. roborovskii), we show that recombination suppression on Xp appears to be independent of major structural rearrangements. The suppressed Xp arm was enriched for several transposable element families and deenriched for genes primarily expressed in placenta, but otherwise showed similar gene densities, expression patterns, and rates of molecular evolution when compared to the recombinant Xq arm. Phodopus Xp gene content and order was also broadly conserved relative to the more distantly related rat X chromosome. These data suggest that widespread suppression of recombination has likely evolved through the transient induction of facultative heterochromatin on the Phodopus Xp arm without major changes in chromosome structure or genetic content. Thus, substantial changes in the recombination landscape have so far had relatively subtle influences on patterns of X-linked molecular evolution in these species.
KW - faster-X evolution
KW - sex chromosome evolution
KW - sex-biased genes
KW - transposable element accumulation
UR - http://www.scopus.com/inward/record.url?scp=85131772429&partnerID=8YFLogxK
U2 - 10.1093/gbe/evac080
DO - 10.1093/gbe/evac080
M3 - Article
C2 - 35642315
AN - SCOPUS:85131772429
SN - 1759-6653
VL - 14
JO - Genome Biology and Evolution
JF - Genome Biology and Evolution
IS - 6
M1 - evac080
ER -