The X chromosome of the German cockroach, Blattella germanica, is homologous to a fly X chromosome despite 400 million years divergence
Abstract Background Sex chromosome evolution is a dynamic process that can proceed at varying rates across lineages. For example, different chromosomes can be sex-linked between closely related species, whereas other sex chromosomes have been conserved for > 100 million years. Cases of long-term...
| Main Authors: | , , |
|---|---|
| Format: | Article |
| Language: | English |
| Published: |
BMC
2019-12-01
|
| Series: | BMC Biology |
| Subjects: | |
| Online Access: | https://doi.org/10.1186/s12915-019-0721-x |
| _version_ | 1818352273223319552 |
|---|---|
| author | Richard P. Meisel Pablo J. Delclos Judith R. Wexler |
| author_facet | Richard P. Meisel Pablo J. Delclos Judith R. Wexler |
| author_sort | Richard P. Meisel |
| collection | DOAJ |
| description | Abstract Background Sex chromosome evolution is a dynamic process that can proceed at varying rates across lineages. For example, different chromosomes can be sex-linked between closely related species, whereas other sex chromosomes have been conserved for > 100 million years. Cases of long-term sex chromosome conservation could be informative of factors that constrain sex chromosome evolution. Cytological similarities between the X chromosomes of the German cockroach (Blattella germanica) and most flies suggest that they may be homologous—possibly representing an extreme case of long-term conservation. Results To test the hypothesis that the cockroach and fly X chromosomes are homologous, we analyzed whole-genome sequence data from cockroaches. We found evidence in both sequencing coverage and heterozygosity that a significant excess of the same genes are on both the cockroach and fly X chromosomes. We also present evidence that the candidate X-linked cockroach genes may be dosage compensated in hemizygous males. Consistent with this hypothesis, three regulators of transcription and chromatin on the fly X chromosome are conserved in the cockroach genome. Conclusions Our results support our hypothesis that the German cockroach shares the same X chromosome as most flies. This may represent the convergent evolution of the X chromosome in the lineages leading to cockroaches and flies. Alternatively, the common ancestor of most insects may have had an X chromosome that resembled the extant cockroach and fly X. Cockroaches and flies diverged ∼ 400 million years ago, which would be the longest documented conservation of a sex chromosome. Cockroaches and flies have different mechanisms of sex determination, raising the possibility that the X chromosome was conserved despite the evolution of the sex determination pathway. |
| first_indexed | 2024-12-13T18:51:01Z |
| format | Article |
| id | doaj.art-761813e8649c44018733e4529824f621 |
| institution | Directory Open Access Journal |
| issn | 1741-7007 |
| language | English |
| last_indexed | 2024-12-13T18:51:01Z |
| publishDate | 2019-12-01 |
| publisher | BMC |
| record_format | Article |
| series | BMC Biology |
| spelling | doaj.art-761813e8649c44018733e4529824f6212022-12-21T23:34:56ZengBMCBMC Biology1741-70072019-12-0117111410.1186/s12915-019-0721-xThe X chromosome of the German cockroach, Blattella germanica, is homologous to a fly X chromosome despite 400 million years divergenceRichard P. Meisel0Pablo J. Delclos1Judith R. Wexler2Department of Biology and Biochemistry, University of HoustonDepartment of Biology and Biochemistry, University of HoustonDepartment of Ecology and Evolution, University of California, DavisAbstract Background Sex chromosome evolution is a dynamic process that can proceed at varying rates across lineages. For example, different chromosomes can be sex-linked between closely related species, whereas other sex chromosomes have been conserved for > 100 million years. Cases of long-term sex chromosome conservation could be informative of factors that constrain sex chromosome evolution. Cytological similarities between the X chromosomes of the German cockroach (Blattella germanica) and most flies suggest that they may be homologous—possibly representing an extreme case of long-term conservation. Results To test the hypothesis that the cockroach and fly X chromosomes are homologous, we analyzed whole-genome sequence data from cockroaches. We found evidence in both sequencing coverage and heterozygosity that a significant excess of the same genes are on both the cockroach and fly X chromosomes. We also present evidence that the candidate X-linked cockroach genes may be dosage compensated in hemizygous males. Consistent with this hypothesis, three regulators of transcription and chromatin on the fly X chromosome are conserved in the cockroach genome. Conclusions Our results support our hypothesis that the German cockroach shares the same X chromosome as most flies. This may represent the convergent evolution of the X chromosome in the lineages leading to cockroaches and flies. Alternatively, the common ancestor of most insects may have had an X chromosome that resembled the extant cockroach and fly X. Cockroaches and flies diverged ∼ 400 million years ago, which would be the longest documented conservation of a sex chromosome. Cockroaches and flies have different mechanisms of sex determination, raising the possibility that the X chromosome was conserved despite the evolution of the sex determination pathway.https://doi.org/10.1186/s12915-019-0721-xSex chromosomeEvolutionInsectArthropod genomicsDosage compensation |
| spellingShingle | Richard P. Meisel Pablo J. Delclos Judith R. Wexler The X chromosome of the German cockroach, Blattella germanica, is homologous to a fly X chromosome despite 400 million years divergence BMC Biology Sex chromosome Evolution Insect Arthropod genomics Dosage compensation |
| title | The X chromosome of the German cockroach, Blattella germanica, is homologous to a fly X chromosome despite 400 million years divergence |
| title_full | The X chromosome of the German cockroach, Blattella germanica, is homologous to a fly X chromosome despite 400 million years divergence |
| title_fullStr | The X chromosome of the German cockroach, Blattella germanica, is homologous to a fly X chromosome despite 400 million years divergence |
| title_full_unstemmed | The X chromosome of the German cockroach, Blattella germanica, is homologous to a fly X chromosome despite 400 million years divergence |
| title_short | The X chromosome of the German cockroach, Blattella germanica, is homologous to a fly X chromosome despite 400 million years divergence |
| title_sort | x chromosome of the german cockroach blattella germanica is homologous to a fly x chromosome despite 400 million years divergence |
| topic | Sex chromosome Evolution Insect Arthropod genomics Dosage compensation |
| url | https://doi.org/10.1186/s12915-019-0721-x |
| work_keys_str_mv | AT richardpmeisel thexchromosomeofthegermancockroachblattellagermanicaishomologoustoaflyxchromosomedespite400millionyearsdivergence AT pablojdelclos thexchromosomeofthegermancockroachblattellagermanicaishomologoustoaflyxchromosomedespite400millionyearsdivergence AT judithrwexler thexchromosomeofthegermancockroachblattellagermanicaishomologoustoaflyxchromosomedespite400millionyearsdivergence AT richardpmeisel xchromosomeofthegermancockroachblattellagermanicaishomologoustoaflyxchromosomedespite400millionyearsdivergence AT pablojdelclos xchromosomeofthegermancockroachblattellagermanicaishomologoustoaflyxchromosomedespite400millionyearsdivergence AT judithrwexler xchromosomeofthegermancockroachblattellagermanicaishomologoustoaflyxchromosomedespite400millionyearsdivergence |