A repeat DNA sequence from the Y chromosome in species of the genus <Emphasis Type="Italic">Microtus</Emphasis> |
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Authors: | J?A?Marchal M?J?Acosta M?Bullejos R?Díaz de la Guardia Email author" target="_blank">A?SánchezEmail author |
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Institution: | (1) Departamento de Biología Experimental, Facultad de Ciencias Experimentales y de la Salud, Universidad de Jaén, E-23071, Jaén, Spain;(2) Departamento de Genética, Facultad de Ciencias, Universidad de Granada, E-18071, Granada, Spain |
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Abstract: | In most mammals, the Y chromosome is composed of a large amount of constitutive heterochromatin. In some Microtus species, this feature is also extended to the X chromosome, resulting in enlarged (giant) sex chromosomes. Several repeated
DNA sequences have been described in the gonosomal heterochromatin of these species, indicating that it has heterogeneous
and species-specific composition and distribution. We have cloned an AT-rich, 851-bp long, repeated DNA sequence specific
for M. cabrerae Y chromosome heterochromatin. The analysis of other species of the genus Microtus indicated that this sequence is also located on the Y chromosome (male-specific) in three species (M. agrestis, M. oeconomus and M. nivalis), present on both Y and X chromosomes and on some autosomes in M. arvalis and absent in the genome of M. guentheri. Our data also suggest that the mechanism of heterochromatin amplification operating on the sex chromosomes could have been
different in each species since the repeated sequences of the gonosomal heterochromatic blocks in M. cabrerae and M. agrestis are different. The absence of this sequence in the mouse genome indicates that its evolutionary origin could be recent. Future
analysis of the species distribution, localization and sequence of this repeat DNA family in arvicolid rodent species could
help to establish the unsolved phylogenetic relationships in this rodent group. |
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Keywords: | heterochromatin Microtus repeat DNA sequences sex chromosomes |
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