X accumulation of LINE-1 retrotransposons in Tokudaia osimensis, a spiny rat with the karyotype XO.
The observation that LINE-1 transposable elements are enriched on the X in comparison to the autosomes led to the hypothesis that LINE-1s play a role in X chromosome inactivation. If this hypothesis is correct, loss of LINE-1 activity would be expected to result in species extinction or in an alternate pathway of dosage compensation. One such alternative pathway would be to evolve a karyotype that does not require dosage compensation between the sexes. Two of the three extant species of the Ryukyu spiny rat Tokudaia have such a karyotype; both males and females are XO. We asked whether this karyotype arose due to loss of LINE-1 activity and thus the loss of a putative component in the X inactivation pathway. Although XO Tokudaia has no need for dosage compensation, LINE-1s have been recently active in Tokudaia osimensis and show higher density on the lone X than on the autosomes.
Department of Biological Sciences, University of Idaho, Moscow, ID 83844-3051, USA.
L A
LA
Scott
A
A
Kuroiwa
Y
Y
Matsuda
H A
HA
Wichman
D020413:3' Untranslated Regions / Q000235:genetics; D020121:5' Untranslated Regions / Q000235:genetics; D000818:Animals; D002874:Chromosome Mapping; D004251:DNA Transposable Elements; D005260:Female; D007621:Karyotyping; D020084:Long Interspersed Nucleotide Elements / Q000235:genetics*; D008297:Male; D009115:Muridae / Q000235:genetics*; D018626:Retroelements / Q000235:genetics; D012729:Sex Chromosome Aberrations; D014960:X Chromosome
D020413:3' Untranslated Regions; D020121:5' Untranslated Regions; D004251:DNA Transposable Elements; D018626:Retroelements