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Background <p><i>Aegilops biuncialis</i>is tetraploid grass species with U<sup>b</sup>U<sup>b</sup>M<sup>b</sup>M<sup>b</sup> genome constitution, distributed in Mediterranean and the Middle East. It carries many valuable traits such as disease resistance, drought tolerance, high micronutrient content, which are in demand of wheat breeding. Transfer of genetic material from <i>Ae. biuncialis</i> is not easy due to substantial modification of U<sup>b</sup> and especially M<sup>b</sup> genomes. Cytogenetic markers permitting easy and reliable chromosome identification will be helpful for successful manipulation with alien genetic material and introgression of useful traits into wheat. Development of chromosome nomenclature is complicated by the significant karyotype diversity of <i>Ae. biuncialis.</i></p> Results <p>We used various combinations of eleven DNA probes for studying intraspecific karyotype divergence of <i>Ae. biuncialis</i> by FISH; among them pTa-566, pTa713 and pSc119.2 probes proved to be most informative for chromosome identification and analysis of karyotype evolution. FISH discriminated three chromosomal groups designated A, B and C and showed that the U<sup>b</sup> genome of <i>Ae. biuncialis</i> is less modified relative to the parental compared to M<sup>b</sup> genome. Based on the obtained results we suggested that <i>Ae. biuncialis</i> originated via multiple hybridization events and the U<sup>b</sup> and M<sup>b</sup> genomes of group A, B, and C were contributed by different forms of <i>Ae. umbellulata</i> and <i>Ae. comosa</i>. The M<sup>b</sup> genome of groups A and C probably derived from <i>Ae. comosa</i> subsp. <i>comosa</i>, whereas in the B-group - from subsp. <i>heldreichii.</i> Divergence of chromosomal groups of <i>Ae. biuncialis</i> was also accompanied by structural chromosome rearrangements. Using multiple DNA probes, we showed that reciprocal translocation between chromosomes 1M<sup>b</sup>L and 7M<sup>b</sup>L followed by pericentric inversion of modified 1M<sup>b</sup> occurred in group A. Intraspecific divergence of <i>Ae. biuncialis</i> was also associated with amplification/ elimination/ redistribution of repetitive DNA families.</p> Conclusions <p>Our study revealed complex genome structure of wild tetraploid grass <i>Ae. biuncialis</i> which might have occurred via multiple hybridization events resulting in formation of three distinct chromosomal groups. Their divergence was accompanied by different chromosomal rearrangements which resulted in formation of highly distinct karyotypes. By using FISH markers, we evaluated the relations between chromosomes of the three groups and developed genetic nomenclature of <i>Ae. biuncialis</i> chromosomes.</p>

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Dynamics of repetitive DNA sequences over the course of evolution and intraspecific divergence of tetraploid goat-grass species Aegilops biuncialis vis

  • 期刊论文

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  • 发表日期：

    2025年11月29日

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  • Ekaterina D. Badaeva,
  • Olga V. Razumova,
  • Maida Jazmin González Franco,
  • Viktoria M. Sokolova,
  • Anna I. Yurkina,
  • Maria Kh. Belousova,
  • Nadezhda N. Chikida,
  • Alexandra Yu. Dragovich,
  • Andrey V. Fisenko,
  • Alexandra V. Amosova,
  • Sergei A. Surzhikov,
  • Mikhail G. Divashuk

摘要

Background

Aegilops biuncialisis tetraploid grass species with UbUbMbMb genome constitution, distributed in Mediterranean and the Middle East. It carries many valuable traits such as disease resistance, drought tolerance, high micronutrient content, which are in demand of wheat breeding. Transfer of genetic material from Ae. biuncialis is not easy due to substantial modification of Ub and especially Mb genomes. Cytogenetic markers permitting easy and reliable chromosome identification will be helpful for successful manipulation with alien genetic material and introgression of useful traits into wheat. Development of chromosome nomenclature is complicated by the significant karyotype diversity of Ae. biuncialis.

Results

We used various combinations of eleven DNA probes for studying intraspecific karyotype divergence of Ae. biuncialis by FISH; among them pTa-566, pTa713 and pSc119.2 probes proved to be most informative for chromosome identification and analysis of karyotype evolution. FISH discriminated three chromosomal groups designated A, B and C and showed that the Ub genome of Ae. biuncialis is less modified relative to the parental compared to Mb genome. Based on the obtained results we suggested that Ae. biuncialis originated via multiple hybridization events and the Ub and Mb genomes of group A, B, and C were contributed by different forms of Ae. umbellulata and Ae. comosa. The Mb genome of groups A and C probably derived from Ae. comosa subsp. comosa, whereas in the B-group - from subsp. heldreichii. Divergence of chromosomal groups of Ae. biuncialis was also accompanied by structural chromosome rearrangements. Using multiple DNA probes, we showed that reciprocal translocation between chromosomes 1MbL and 7MbL followed by pericentric inversion of modified 1Mb occurred in group A. Intraspecific divergence of Ae. biuncialis was also associated with amplification/ elimination/ redistribution of repetitive DNA families.

Conclusions

Our study revealed complex genome structure of wild tetraploid grass Ae. biuncialis which might have occurred via multiple hybridization events resulting in formation of three distinct chromosomal groups. Their divergence was accompanied by different chromosomal rearrangements which resulted in formation of highly distinct karyotypes. By using FISH markers, we evaluated the relations between chromosomes of the three groups and developed genetic nomenclature of Ae. biuncialis chromosomes.