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Pilkington SM, Tahir J, Hilario E, Gardiner SE, Chagné D, Catanach A, McCallum J, Jesson L, Fraser LG, McNeilage MA, Deng C, Crowhurst RN, Datson PM, Zhang Q. Genetic and cytological analyses reveal the recombination landscape of a partially differentiated plant sex chromosome in kiwifruit. BMC Plant Biol 2019; 19:172. [PMID: 31039740 PMCID: PMC6492441 DOI: 10.1186/s12870-019-1766-2] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/26/2018] [Accepted: 04/08/2019] [Indexed: 05/10/2023]
Abstract
BACKGROUND Angiosperm sex chromosomes, where present, are generally recently evolved. The key step in initiating the development of sex chromosomes from autosomes is the establishment of a sex-determining locus within a region of non-recombination. To better understand early sex chromosome evolution, it is important to determine the process by which recombination is suppressed around the sex determining genes. We have used the dioecious angiosperm kiwifruit Actinidia chinensis var. chinensis, which has an active-Y sex chromosome system, to study recombination rates around the sex locus, to better understand key events in the development of sex chromosomes. RESULTS We have confirmed the sex-determining region (SDR) in A. chinensis var. chinensis, using a combination of high density genetic mapping and fluorescent in situ hybridisation (FISH) of Bacterial Artificial Chromosomes (BACs) linked to the sex markers onto pachytene chromosomes. The SDR is a subtelomeric non-recombining region adjacent to the nucleolar organiser region (NOR). A region of restricted recombination of around 6 Mbp in size in both male and female maps spans the SDR and covers around a third of chromosome 25. CONCLUSIONS As recombination is suppressed over a similar region between X chromosomes and between and X and Y chromosomes, we propose that recombination is suppressed in this region because of the proximity of the NOR and the centromere, with both the NOR and centromere suppressing recombination, and this predates suppressed recombination due to differences between X and Y chromosomes. Such regions of suppressed recombination in the genome provide an opportunity for the evolution of sex chromosomes, if a sex-determining locus develops there or translocates into this region.
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Affiliation(s)
- S. M. Pilkington
- The New Zealand Institute for Plant and Food Research Limited (PFR), Private Bag 92169, Auckland, 1142 New Zealand
| | - J. Tahir
- PFR, Private Bag 11600, Palmerston North, 4442 New Zealand
| | - E. Hilario
- The New Zealand Institute for Plant and Food Research Limited (PFR), Private Bag 92169, Auckland, 1142 New Zealand
| | - S. E. Gardiner
- PFR, Private Bag 11600, Palmerston North, 4442 New Zealand
| | - D. Chagné
- PFR, Private Bag 11600, Palmerston North, 4442 New Zealand
| | - A. Catanach
- PFR, Private Bag 4704, Christchurch, 8140 New Zealand
| | - J. McCallum
- PFR, Private Bag 4704, Christchurch, 8140 New Zealand
| | - L. Jesson
- PFR, Private Bag 1401, Havelock North, 4157 New Zealand
| | - L. G. Fraser
- The New Zealand Institute for Plant and Food Research Limited (PFR), Private Bag 92169, Auckland, 1142 New Zealand
| | - M. A. McNeilage
- The New Zealand Institute for Plant and Food Research Limited (PFR), Private Bag 92169, Auckland, 1142 New Zealand
| | - C. Deng
- The New Zealand Institute for Plant and Food Research Limited (PFR), Private Bag 92169, Auckland, 1142 New Zealand
| | - R. N. Crowhurst
- The New Zealand Institute for Plant and Food Research Limited (PFR), Private Bag 92169, Auckland, 1142 New Zealand
| | - P. M. Datson
- The New Zealand Institute for Plant and Food Research Limited (PFR), Private Bag 92169, Auckland, 1142 New Zealand
| | - Q. Zhang
- CAS Key Laboratory of Plant Germplasm Enhancement and Specialty Agriculture, Wuhan Botanical Garden, Chinese Academy of Sciences, Wuhan, 430074 China
- The Innovative Academy of Seed Design, Chinese Academy of Sciences, Wuhan, 430074 China
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