Abstract In cultivated tetraploid potato (Solanum tuberosum), reduction to diploidy (dihaploidy) allows for hybridization to diploids and introgression breeding and may facilitate the production of inbreds. Pollination with haploid inducers yields maternal dihaploids, as well as triploid and tetraploid hybrids. Dihaploids may result from parthenogenesis, entailing the development of embryos from unfertilized eggs, or genome elimination, entailing missegregation and the loss of paternal chromosomes. A sign of genome elimination is the occasional persistence of haploid inducer DNA in some dihaploids. We characterized the genomes of 919 putative dihaploids and 134 hybrids produced by pollinating tetraploid clones with three haploid inducers: IVP35, IVP101, and PL-4. Whole-chromosome or segmental aneuploidy was observed in 76 dihaploids, with karyotypes ranging from 2n=2x-1=23 to 2n=2x+3=27. Of the additional chromosomes in 74 aneuploids, 66 were from the non-inducer parent and 8 from the inducer parent. Overall, we detected full or partial chromosomes from the haploid inducer parent in 0.87% of the dihaploids, irrespective of parental genotypes. Chromosomal breaks commonly affected the paternal genome in the dihaploid and tetraploid progeny, but not in the triploid progeny, correlating instability to sperm ploidy and to haploid induction. The residual haploid inducer DNA discovered in the progeny is consistent withmore »
This content will become publicly available on December 1, 2023
Decay of homologous chromosome pairs and discovery of males in the thelytokous fungus-growing ant Mycocepurus smithii
Abstract The prevalent mode of reproduction among ants is arrhenotokous parthenogenesis where unfertilized eggs give rise to haploid males and fertilized eggs develop into diploid females. Some ant species are capable of thelytokous parthenogenesis, a type of asexual reproduction where females develop from unfertilized diploid eggs. Thelytoky is well-documented in more than 20 ant species. Cytogenetic data are available for six species demonstrating that some thelytokous ant species are capable of producing males occasionally as well as maintaining their chromosome numbers and proper chromosome pairings. Mycocepurus smithii is a thelytokous fungus-growing ant species that inhabits large parts of Central and South America. Cytogenetic data are unavailable for M. smithii and male individuals were never documented for this species, although the presence of males is expected because genetic recombination was observed in a few sexually reproducing populations in Brazil and haploid sperm was documented from the spermathecae of M. smithii queens. This study aims at comparatively studying asexual and sexual populations of M. smithii using classical and molecular cytogenetic methods to test whether karyotype configuration is modified according to the mode of reproduction in M. smithii . Moreover, we report the discovery of M. smithii males from a sexually reproducing population more »
- Award ID(s):
- 1943626
- Publication Date:
- NSF-PAR ID:
- 10385652
- Journal Name:
- Scientific Reports
- Volume:
- 12
- Issue:
- 1
- ISSN:
- 2045-2322
- Sponsoring Org:
- National Science Foundation
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