Abstract
Wheat cultivar Chinese Spring (Triticum aestivum L. em. Thell.) was crossed with cultivars Hope, Cheyenne and Timstein. In all three hybrids, the frequencies of pollen mother cells (PMCs) with univalents at metaphase I (MI) were higher than those in the parental cultivars. No multivalents were observed in the hybrids, indicating that the cultivars do not differ by translocations. Thirty-one Chinese Spring telosomic lines were then crossed with substitution lines in which single chromosomes of the three cultivars were substituted for their Chinese Spring homologues. The telosomic lines were also crossed with Chinese Spring. Data were collected on the frequencies (% of PMCs) of pairing of the telesomes with their homologues at MI and the regularity of pairing of the remaining 20 pairs of Chinese Spring chromosomes in the monotelodisomics obtained from these crosses. The reduced MI pairing in the intercultivar hybrids was caused primarily by chromosome differentiation, rather than by specific genes. Because the differentiation involved a large part of the chromosome complement in each hybrid, it was concluded that it could not be caused by structural changes such as inversions or translocations. In each case, the differentiation appeared to be unevenly distributed among the three wheat genomes. It is proposed that the same kind of differentiation, although of greater magnitude, differentiates homoeologous chromosomes and is responsible, together with structural differentiation, for poor chromosome pairing in interspecific hybrids.
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- Doyle G G. Preferential Pairing in Structural Heterozygotes of Zea Mays. Genetics. 1963 Aug;48(8):1011–1027. doi: 10.1093/genetics/48.8.1011. [DOI] [PMC free article] [PubMed] [Google Scholar]
- GERSTEL D. U., PHILLIPS L. L. Segregation of synthetic amphiploids in Gossypium and Nicotiana. Cold Spring Harb Symp Quant Biol. 1958;23:225–237. doi: 10.1101/sqb.1958.023.01.025. [DOI] [PubMed] [Google Scholar]
- GRELL E. H. Variations in preferential segregation of chromosome two in triploid females of Drosophila melanogaster. Genetics. 1961 Oct;46:1267–1271. doi: 10.1093/genetics/46.10.1267. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Gill B. S., Kimber G. Giemsa C-banding and the evolution of wheat. Proc Natl Acad Sci U S A. 1974 Oct;71(10):4086–4090. doi: 10.1073/pnas.71.10.4086. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Hanson W D. The Breakup of Initial Linkage Blocks under Selected Mating Systems. Genetics. 1959 Sep;44(5):857–868. doi: 10.1093/genetics/44.5.857. [DOI] [PMC free article] [PubMed] [Google Scholar]
- John B., Miklos G. L. Functional aspects of satellite DNA and heterochromatin. Int Rev Cytol. 1979;58:1–114. doi: 10.1016/s0074-7696(08)61473-4. [DOI] [PubMed] [Google Scholar]
- Miklos G. L., John B. Heterochromatin and satellite DNA in man: properties and prospects. Am J Hum Genet. 1979 May;31(3):264–280. [PMC free article] [PubMed] [Google Scholar]
- Miklos G. L., Willcocks D. A., Baverstock P. R. Restriction endonuclease and molecular analyses of three rat genomes with special reference to chromosome rearrangement and speciation problems. Chromosoma. 1980;76(3):339–363. doi: 10.1007/BF00327271. [DOI] [PubMed] [Google Scholar]
- Stern H., Hotta Y. Biochemical controls of meiosis. Annu Rev Genet. 1973;7:37–66. doi: 10.1146/annurev.ge.07.120173.000345. [DOI] [PubMed] [Google Scholar]
- Sved J. A. Telomere attachment of chromosomes. Some genetical and cytological consequences. Genetics. 1966 Apr;53(4):747–756. doi: 10.1093/genetics/53.4.747. [DOI] [PMC free article] [PubMed] [Google Scholar]
- TEN BERGE B. S. Operatieve behandeling bij tuberculose van vrouwelijke genitalia interna met toediening van P. A. S. en streptomycine. Geneeskd Gids. 1952 Sep 18;30(19):405–408. [PubMed] [Google Scholar]