AI Article Synopsis
- Researchers found a unique extra chromosome, called a germline-restricted chromosome (GRC), in zebra and Bengalese finches, which is only passed on through female birds and not present in their body cells or sperm.
- GRCs vary in size and genetic makeup across all 16 songbird species studied but are not found in eight other types of birds, suggesting a specific evolutionary trait of songbirds.
- The study also indicates that the GRC likely originated in the common ancestor of songbirds and has significantly evolved in their descendant species, showing minimal similarities between different songbird GRCs.
Article Abstract
An unusual supernumerary chromosome has been reported for two related avian species, the zebra and Bengalese finches. This large, germline-restricted chromosome (GRC) is eliminated from somatic cells and spermatids and transmitted via oocytes only. Its origin, distribution among avian lineages, and function were mostly unknown so far. Using immunolocalization of key meiotic proteins, we found that GRCs of varying size and genetic content are present in all 16 songbird species investigated and absent from germline genomes of all eight examined bird species from other avian orders. Results of fluorescent in situ hybridization of microdissected GRC probes and their sequencing indicate that GRCs show little homology between songbird species and contain a variety of repetitive elements and unique sequences with paralogs in the somatic genome. Our data suggest that the GRC evolved in the common ancestor of all songbirds and underwent significant changes in the extant descendant lineages.
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| http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6575587 | PMC |
| http://dx.doi.org/10.1073/pnas.1817373116 | DOI Listing |
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