U.S. flagAn official website of the United States government
                    Here's how you know **Official websites use .gov**
                            
                            A **.gov** website belongs to an official government organization in the United States.
 **Secure .gov websites use HTTPS**
                            
                            A **lock** (                            
                              A locked padlock                                                      
                            
                            ) or **https://** means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.


Menu Agricultural Research Service
						
                    U.S. DEPARTMENT OF AGRICULTURE
 close



Research
                Research Home
                            National Programs
                            Research Projects
                            Scientific Manuscripts
                            International Engagement
                            Scientific Software/Models
                            Databases and Datasets
                            Office of Scientific Quality Review
            Media
                News & Features
                            Multimedia
                            Briefing Room
                            Down on the Farm
                            Press Room
                            Science in Your Shopping Cart
                            Scientific Discoveries
                            Tellus
                            Under the Microscope
            About ARS
                About ARS Home
                            Staff Directory
                            Labs and Research Centers (Map)
                            Headquarter Offices
                            Organizational Chart
                            Employee Services (REE Employees Only)
                            Office of Outreach, Diversity, and Equal Opportunity
            Work With Us
                Work With Us Home
                            ARS Vacancies at USAJOBS
                            Careers at ARS Information
                            Scientific Collaborations
                            Extramural Agreements
                            1890 Faculty Research Sabbatical ProgramSearch small
                    Search
            
            ARS Home
                                About ARS
                                Contact Us




ARS Home Research Publications at this Location





- ARS National Programs
- Search for a scientific manuscript
- Search for a research project
- ARS Software
- Programs and Projects
- Collaborations
- Subjects of Investigation
- Publications

Title:   Author  item
                                            SPIGLER, RACHEL - UNIV OF PITTSBURGHitem
                                            Lewers, Kimberlyitem
                                            MANN, DORRIE - WASHINGTON STATE UNIVitem
                                            ASHMAN, TIA-LYNN - UNIV OF PITTSBURGH
  Submitted to: Heredity
                                    Publication Type: Peer Reviewed Journal
                                    Publication Acceptance Date: 6/9/2008
                                    Publication  Date: 9/18/2008
                                    Citation: Spigler, R., Lewers, K.S., Mann, D., Ashman, T. 2008. Genetic mapping of sex determination in a wild strawberry, Fragaria virginiana reveals earliest form of sex chromosome. Heredity. 101:507-517. Interpretive Summary: Scientists who develop improved strawberry varieties sometimes use a wild strawberry as a parent, because the wild strawberry may be the only source of the trait, such as resistance to a new disease. The particular wild strawberry needed may be one whose flowers have no male parts (anthers and pollen) or whose flowers fail to set fruit even when pollinated. Therefore, additional information is needed about the inheritance of the genes that cause lack of male parts and the genes that control lack of fruit set. We made a large family of 184 seedlings from cross-pollinating two wild strawberry plants, one lacking male parts, and one that has, in the past, produced seedlings that produced no fruit. We characterized all 184 for the presence of male parts and for fruit set, as well as the presence or absence of 217 specific DNA sequences. We found that the gene controlling production of male parts is on the same chromosome as the gene(s) controlling fruit set. We also found a specific DNA sequence very close to them both on that same chromosome. This information is useful to scientists developing improved strawberry varieties.
                                Technical Abstract: The evolution of separate sexes (dioecy) from hermaphroditism is one of the major evolutionary transitions in plants and this transition can be accompanied by the development of sex chromosomes. However, we are now just beginning to gain insight into the initial stages of sex chromosome evolution via studies in species with transitional breeding systems. Here we inform on the genetic mechanism of sex determination in the octoploid subdioecious wild strawberry, F. virginiana Mill. by creating a SSR-based genetic map and mapping sex determination as two qualitative traits pertaining to male and female function.  The resultant map was comprised of 217 markers arranged into 42 linkage groups with an average marker spacing of 13.4 cM.  Total map length was 2399.3 cM.  We estimated that approximately 70% and 91% of the total F. virginiana genetic map resides within 10 and 20 cM of a marker on this map, respectively.  Both sex expression traits mapped to the same linkage group along with two SSR markers. These traits were separated by approximately 6 cM. Our phenotypic and genetic mapping results support a model of gender determination with at least two linked loci (or gene regions) with major effects.  Evidence of recombination between the loci indicates both female and male heterogamety exist in this species. And some, but not all, of the hallmarks of incipient sex chromosomes, suggest that F. virginiana perhaps represents a species with the youngest example of a sex chromosome in plants and thus a novel model system for the study of sex chromosome evolution.


Return to top


Connect with ARS Sign up


ARS Home
                            USDA.gov
                            Plain Writing
                            Policies & Links
                            Civil Rights Statements
                            FOIA
                            Accessibility Statement
                            Privacy Policy
                            Non-Discrimination Statement
                            Quality of Information
                            USA.gov
                            WhiteHouse.gov