Repeat associated mechanisms of genome evolution and function revealed by the Mus caroli and Mus pahari genomes

  • D Thybert, M Roller, FCP Navarro, I Fiddes, I Streeter, C Feig, D Martin-Galvez, M Kolmogorov, V Janoušek, W Akanni, B Aken, S Aldridge, V Chakrapani, W Chow, L Clarke, C Cummins, A Doran, M Dunn, L Goodstadt, K Howe, M Howell, AA Josselin, RC Karn, CM Laukaitis, L Jingtao, F Martin, M Muffato, S Nachtweide, MA Quail, C Sisu, M Stanke, K Stefflova, C Van Oosterhout, F Veyrunes, B Ward, F Yang, G Yazdanifar, A Zadissa, DJ Adams, A Brazma, M Gerstein, B Paten, S Pham, TM Keane, DT Odom, P Flicek. Repeat associated mechanisms of genome evolution and function revealed by the Mus caroli and Mus pahari genomes. Genome Res 2018;28(4):448–459. doi:10.1101/gr.234096.117
    [BibTeX] [Abstract]

    Understanding the mechanisms driving lineage-specific evolution in both primates and rodents has been hindered by the lack of sister clades with a similar phylogenetic structure having high-quality genome assemblies. Here, we have created chromosome-level assemblies of the Mus caroli and Mus pahari genomes. Together with the Mus musculus and Rattus norvegicus genomes, this set of rodent genomes is similar in divergence times to the Hominidae (human-chimpanzee-gorilla-orangutan). By comparing the evolutionary dynamics between the Muridae and Hominidae, we identified punctate events of chromosome reshuffling that shaped the ancestral karyotype of Mus musculus and Mus caroli between 3 and 6 million yr ago, but that are absent in the Hominidae. Hominidae show between four- and sevenfold lower rates of nucleotide change and feature turnover in both neutral and functional sequences, suggesting an underlying coherence to the Muridae acceleration. Our system of matched, high-quality genome assemblies revealed how specific classes of repeats can play lineage-specific roles in related species. Recent LINE activity has remodeled protein-coding loci to a greater extent across the Muridae than the Hominidae, with functional consequences at the species level such as reproductive isolation. Furthermore, we charted a Muridae-specific retrotransposon expansion at unprecedented resolution, revealing how a single nucleotide mutation transformed a specific SINE element into an active CTCF binding site carrier specifically in Mus caroli, which resulted in thousands of novel, species-specific CTCF binding sites. Our results show that the comparison of matched phylogenetic sets of genomes will be an increasingly powerful strategy for understanding mammalian biology.

    @Article{29563166,
    author = {Thybert D and Roller M and Navarro FCP and Fiddes I and Streeter I and Feig C and Martin-Galvez D and Kolmogorov M and Janoušek V and Akanni W and Aken B and Aldridge S and Chakrapani V and Chow W and Clarke L and Cummins C and Doran A and Dunn M and Goodstadt L and Howe K and Howell M and Josselin AA and Karn RC and Laukaitis CM and Jingtao L and Martin F and Muffato M and Nachtweide S and Quail MA and Sisu C and Stanke M and Stefflova K and Van Oosterhout C and Veyrunes F and Ward B and Yang F and Yazdanifar G and Zadissa A and Adams DJ and Brazma A and Gerstein M and Paten B and Pham S and Keane TM and Odom DT and Flicek P},
    title = {Repeat associated mechanisms of genome evolution and function revealed by the Mus caroli and Mus pahari genomes},
    journal = {Genome Res},
    volume = {28},
    number = {4},
    pages = {448--459},
    year = {2018},
    doi = {10.1101/gr.234096.117},
    howpublished = {Advanced online publication: 21 March 2018},
    note = {First posted as a preprint: 2 July 2017},
    abstract = {Understanding the mechanisms driving lineage-specific evolution in both primates and rodents has been hindered by the lack of sister clades with a similar phylogenetic structure having high-quality genome assemblies. Here, we have created chromosome-level assemblies of the Mus caroli and Mus pahari genomes. Together with the Mus musculus and Rattus norvegicus genomes, this set of rodent genomes is similar in divergence times to the Hominidae (human-chimpanzee-gorilla-orangutan). By comparing the evolutionary dynamics between the Muridae and Hominidae, we identified punctate events of chromosome reshuffling that shaped the ancestral karyotype of Mus musculus and Mus caroli between 3 and 6 million yr ago, but that are absent in the Hominidae. Hominidae show between four- and sevenfold lower rates of nucleotide change and feature turnover in both neutral and functional sequences, suggesting an underlying coherence to the Muridae acceleration. Our system of matched, high-quality genome assemblies revealed how specific classes of repeats can play lineage-specific roles in related species. Recent LINE activity has remodeled protein-coding loci to a greater extent across the Muridae than the Hominidae, with functional consequences at the species level such as reproductive isolation. Furthermore, we charted a Muridae-specific retrotransposon expansion at unprecedented resolution, revealing how a single nucleotide mutation transformed a specific SINE element into an active CTCF binding site carrier specifically in Mus caroli, which resulted in thousands of novel, species-specific CTCF binding sites. Our results show that the comparison of matched phylogenetic sets of genomes will be an increasingly powerful strategy for understanding mammalian biology.},}

Description

Understanding the mechanisms driving lineage-specific evolution in both primates and rodents has been hindered by the lack of sister clades with a similar phylogenetic structure having high-quality genome assemblies. Here, we have created chromosome-level assemblies of the  Mus caroli  and  Mus pahari  genomes. Together with the  Mus musculus  and  Rattus norvegicus  genomes, this set of rodent genomes is similar in divergence times to the Hominidae (human-chimpanzee-gorilla-orangutan). By comparing the evolutionary dynamics between the Muridae and Hominidae, we identified punctate events of chromosome reshuffling that shaped the ancestral karyotype of  Mus musculus  and  Mus caroli  between 3 to 6 MYA, but that are absent in the Hominidae. In fact, Hominidae show between four- and seven-fold lower rates of nucleotide change and feature turnover in both neutral and functional sequences suggesting an underlying coherence to the Muridae acceleration. Our system of matched, high-quality genome assemblies revealed how specific classes of repeats can play lineage-specific roles in related species. For example, recent LINE activity has remodeled protein-coding loci to a greater extent across the Muridae than the Hominidae, with functional consequences at the species level such as reproductive isolation. Furthermore, we charted a Muridae-specific retrotransposon expansion at unprecedented resolution, revealing how a single nucleotide mutation transformed a specific SINE element into an active CTCF binding site carrier specifically in  Mus caroli . This process resulted in thousands of novel, species-specific CTCF binding sites. Our results demonstrate that the comparison of matched phylogenetic sets of genomes will be an increasingly powerful strategy for understanding mammalian biology.

Full details are provided in our open access publication in  Genome Research

Data access

The genome assemblies of Mus caroli and Mus pahari were submitted to the European Nucleotide Archive and are available with accession numbers  GCA_900094665  for  Mus caroli  and  GCA_900095145  for  Mus pahari . All reads from the ChIP-seq and RNA-seq experiments in this study were submitted to ArrayExpress and are available with accession numbers  E-MTAB-5768  (RNA-seq) and  E-MTAB-5769  (ChIP-seq).

Transposible element annotation

The results of RepeatMasker identifications were postprocessed to merge fragmented hits and remove non-transposable repeats to create the final set used in this study. The results of postprocessing are available  here . The columns in the postprocessed files correspond to:

Column number Description
1 Toplevel genomic segment, i.e. chromosome, scaffold
2 Start position of match in genomic segment
3 End position of match in genomic segment
4 RepeatMasker result: % substitutions in matching region compared to the consensus
5 RepeatMasker result: % of bases opposite a gap in the query sequence (deleted bp)
6 RepeatMasker result: % of bases opposite a gap in the repeat consensus (inserted bp)
7 Transposable element classification: transposable element class
8 Transposable element classification: transposable element family
9 Transposable element classification: transposable element subfamily
10 Unique id created for this study

Whole genome alignments

The whole genome alignments used in this study are available  here  in Ensembl Multi Format (EMF) and multiple alignment format (MAF). Pairwise whole genome alignments were generated using LastZ and multiple whole genome alignments with the Enredo-Pecan-Ortheus (EPO) pipeline. For more information please refer to the Methods in our  paper .

CTCF occupancy sites

The peak sets per biological replicate are available in ArrayExpress under the accession number  E-MTAB-5769 . The peaks present in at least two biological replicates are available  here . The B2_Mm1 transposable elements used as input for building the neighbour joining tree are available  here . For more information please refer to the Methods in our  paper .

CTCF occupancy sites associated with repetitive elements are available  here . The columns in the postprocessed files describe:

Column name Description
PeakChr Toplevel genomic segment containing the CTCF peak, i.e. chromosome, scaffold
PeakStart Start position of CTCF peak in genomic segment
PeakEnd End position of CTCF peak in genomic segment
RepeatChr Toplevel genomic segment containing the repeat element, i.e. chromosome, scaffold consensus
RepeatStart Start position of repeat element in genomic segment
RepeatEnd End position of repeat element in genomic segment
RepeatClass Transposable element classification: transposable element class
RepeatFamily Transposable element classification: transposable element family
RepeatSubfamily Transposable element classification: transposable element subfamily

Results of multiple alignments of CTCF sites between the rodents are available  here . The name of the file corresponds to the species which was used as query to align to other species. The first column contains all CTCF sites from the query species, and each following column an alignment to another species. If a column contains genomic coordinates, a bound CTCF site is aligned. A lack of aligned CTCF sites is marked with an “X”. A row with “X” in all columns except the first represents a species-specific CTCF binding site. The position of peaks is in “Chr:Start-End” format.

Mus pahari breakpoints

chr1: mm_7:27,524,252-end + mm_19:start-end
                chr2: mm_5:start-30,341,378 + mm_6:strt-end
                chr3: mm_2:23,133,000-end
                chr4: mm_3:start-end
                chr5: mm_1:18,015,577-end
                chr6: mm_4:45,383,207-end
                chr7: mm_12:start-end
                chr8: mm_14:start-end
                chr9: mm_10:33,415,951-end
                chr10: mm_9:start-end
                chr11: mm_13:[66,989,676/67,139,392]-end + mm_15:start-32,682,454
                chr12: mm_16:start-end
                chr13: mm_11:start-31,004,372+mm_5:33,090,849-[109,638,275/110,356,165]
                chr14: mm_11:31,014,735-end
                chr15: mm_18:start-end
                chr16: mm_2:start-23,116,788 + mm_13:start-[66,989,676/67,139,392]
                chr17: mm_15:32,682,454-end
                chr18: mm_17:31,811,330-end
                chr19: mm_7:start-27,524,252+ mm_8:start-75,294,883
                chr20: mm_8:75,299,631-end
                chr21: mm_17:start-27,052,643 + mm_10:start-33,381,753
                chr22: mm_1:start-17,966,305 + mm_4:start-45,383,207-end
                chr23: mm_5:[109,638,275/110,356,165]-end
                

The above lines refer to the composition of the Music pahari chromosomes. For example, chr1 of Mus pahari is composed of chr7 of Mus musculus starting from the position 27,524,252 until the end and then chr19 of Mus musculus from start to end. This gives a break point from the Mus musculus perspective.

For data points such as [66,989,676/67,139,392], this results from the array CGH being done twice. We have the mean between these two values for the analysis of repeat enrichment in the paper.

Mouse-rat breakpoints

chr1 rn_5:start-13Mb + rn_9:24-104Mb + rn_13:start-end
                chr2:rn_17:70Mb-end + rn_3:start-end
                chr3:rn_2:87Mb-end
                chr4:rn_5:16Mb- end
                chr5:rn_4:start-28Mb + rn_14:start-83Mb + rn_chr12:start-end
                chr6: rn_chr4:28Mb-end
                chr7:rn_1:63Mb-218Mb
                chr8:rn_16:19Mb-end+ rn_19:start-end
                chr9:rn_8:start-end
                chr10:rn_1:start-44Mb+ rn_20:10Mb-end+rn_7:start-67Mb
                chr11:rn_14:83Mb-end + rn_10:15Mb-end
                chr12:rn_6:27Mb-end
                chr13:rn_17:start-70Mb + rn_2:start-51Mb
                chr14:rn_15:start-23Mb + rn_16:start-18Mb + rn_15:23Mb-end
                chr15:rn_2:52Mb-86Mb + rn_7:71Mb-end
                chr16:rn_10:start-12Mb + rn_11:start-end
                chr17:rn_1:44Mb-62Mb + rn_20:start-10Mb +  rn_9:start-24Mb +rn_9:104Mb-end + rn_6:start-25Mb
                chr18:rn_17:54Mb-62Mb + rn_18:start-end
                chr19:rn_1:218Mb-end
                

The mouse rat synteny breaks have been defined using the  Ensembl synteny tool . In order to match the chromosome painting resolution we only retained breaks involved in inter-chromosome rearrangement involved in rearrangement with a size of 5Mb or more.