Abstract
MAIN CONCLUSIONS: Giant genomes in Alstroemeria have maintained structural conservation for ~18.4 million years, whereas satellite DNA amplification and elimination constitutes the main dynamic force underlying heterochromatin diversification and longitudinal chromosomal differentiation. Repetitive sequences are major components of plant genomes and play key roles in genome size evolution and structural variation. Alstroemeria L. is a genus of monocotyledonous plants with giant genomes (1C ≈ 25 Gb), native to the Americas and distributed into two distinct lineages: the Brazilian/Argentinean clade and the Chilean grade. Despite their ancient separation and differences in heterochromatin distribution, all species share a highly conserved chromosome number (2n = 16), with only minor variation in chromosome morphology. Here, we characterized the repetitive DNA fraction of six Chilean species, one Argentinean species, and two Brazilian species, and mapped the most abundant repeats on representative chromosomes from each lineage. LTR Ty3/gypsy Tekay retrotransposons were the predominant repetitive elements, accounting for 30.63-39.91% of the genome across all analyzed species and largely explaining genome size variation. Notably, despite their giant size, Alstroemeria genomes exhibited a relatively low overall proportion of repetitive DNA (up to ~68%), consistent with slow repeat removal and the accumulation of degraded sequences, as predicted for genomes of this size. Satellite DNA represented 0.23-3.42% of the genome, with most satellite families shared between the Brazilian and Chilean species. Nevertheless, despite the divergence of the Brazilian lineage approximately 9.2 million years ago, marked differences in satellite abundance and chromosomal distribution were observed. Our results indicate that giant genome evolution in Alstroemeria is characterized by long-term conservation of karyotype structure and transposable element composition, whereas satellite DNA constitutes a key dynamic component associated with heterochromatin diversification and longitudinal chromosomal differentiation between the Chilean and Brazilian lineages.
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Claims 8
Claim · model-written summary
LTR Ty3/gypsy Tekay retrotransposons were the predominant repetitive elements in all analyzed Alstroemeria species, accounting for 30.63-39.91% of the genome.
- Taxon
- Alstroemeria
Alstroemeriat0 - Outcome
- predominant repetitive elementse0
- Value
- 30.63-39.91% of the genomee0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“genus Alstroemeria L.”
e0“LTR Ty3/gypsy Tekay retrotransposons were the predominant repetitive elements, accounting for 30.63-39.91% of the genome across all analyzed species”
Claim · model-written summary
LTR Ty3/gypsy Tekay retrotransposons largely explained genome size variation among the analyzed Alstroemeria species.
- Taxon
- AlstroemeriaAlstroemeriat0
- Outcome
- genome size variatione0
- Qualifier
- LTR Ty3/gypsy Tekay retrotransposonse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“genus Alstroemeria L.”
e0“LTR Ty3/gypsy Tekay retrotransposons were the predominant repetitive elements, accounting for 30.63-39.91% of the genome across all analyzed species and largely explaining genome size variation”
Claim · model-written summary
Alstroemeria genomes had a relatively low overall proportion of repetitive DNA, up to about 68%, consistent with slow repeat removal.
- Taxon
- AlstroemeriaAlstroemeriae0
- Outcome
- overall proportion of repetitive DNAe0
- Value
- ~68%e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Alstroemeria genomes exhibited a relatively low overall proportion of repetitive DNA (up to ~68%)”
Claim · model-written summary
Satellite DNA represented 0.23-3.42% of the Alstroemeria genome.
- Taxon
- AlstroemeriaAlstroemeriat0
- Outcome
- Satellite DNAe0
- Value
- 0.23-3.42%e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“genus Alstroemeria L.”
e0“Satellite DNA represented 0.23-3.42% of the genome”
Claim · model-written summary
Most satellite families were shared between the Brazilian and Chilean Alstroemeria species.
- Taxon
- AlstroemeriaAlstroemeriat0
- Outcome
- most satellite families sharede0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“genus Alstroemeria L.”
e0“most satellite families shared between the Brazilian and Chilean species”
Claim · model-written summary
Marked differences in satellite abundance and chromosomal distribution were observed between the Brazilian and Chilean lineages of Alstroemeria.
- Taxon
- AlstroemeriaAlstroemeriat0
- Outcome
- satellite abundance and chromosomal distributione0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“genus Alstroemeria L.”
e0“marked differences in satellite abundance and chromosomal distribution were observed”
Claim · model-written summary
The authors conclude that giant genome evolution in Alstroemeria is characterized by long-term conservation of karyotype structure and transposable element composition.
- Taxon
- AlstroemeriaAlstroemeriae0
- Outcome
- long-term conservation of karyotype structure and transposable element compositione0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“giant genome evolution in Alstroemeria is characterized by long-term conservation of karyotype structure and transposable element composition”
Claim · model-written summary
The authors conclude that satellite DNA is a key dynamic component associated with heterochromatin diversification and chromosomal differentiation between the Chilean and Brazilian lineages.
- Taxon
- AlstroemeriaAlstroemeriat0
- Material
- Chilean and Brazilian lineagese0
- Outcome
- heterochromatin diversification and longitudinal chromosomal differentiatione0
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“genus Alstroemeria L.”
e0“satellite DNA constitutes a key dynamic component associated with heterochromatin diversification and longitudinal chromosomal differentiation between the Chilean and Brazilian lineages”