Independent Origins of New Sex-Linked Chromosomes in Drosophila Species
Author Information
Author(s): Sergio V. Flores, Amy L. Evans, Bryant F. McAllister
Primary Institution: University of Iowa
Hypothesis
Are the rearranged sex chromosomes in the melanica and robusta species groups derived through a common origin, or are the rearrangements derived through at least two independent origins?
Conclusion
The study concludes that the independent acquisition of new chromosomal arms by the sex chromosomes in the melanica and robusta species groups represents a case of striking convergence at the karyotypic level.
Supporting Evidence
- The hypothesis of independent origins of rearranged sex chromosomes is significantly more likely than a single common origin.
- Phylogenetic analysis indicates two separate lineages with metacentric sex chromosomes arising from independent fusions.
- Estimates suggest the age of the rearranged sex chromosomes in the melanica group is around 8 million years.
Takeaway
Scientists studied fruit flies to see how their sex chromosomes changed over time and found that two different groups of flies developed similar changes independently.
Methodology
Phylogenetic analysis using two mitochondrial and two nuclear gene sequences to reconstruct relationships among species with fused and unfused sex chromosomes.
Limitations
The study is limited by the number of species analyzed and the phylogenetic relationships within and between the robusta and melanica species groups are not fully resolved.
Statistical Information
P-Value
p<0.05
Confidence Interval
8 My for melanica group; 10–15 My for robusta group
Statistical Significance
p<0.05
Digital Object Identifier (DOI)
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