| Autor: |
Gonzalez-Sanchez, M, Gonzalez-Gonzalez, E, Molina, F, Chiavarino, A M, Rosato, M, Puertas, M J |
| Předmět: |
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| Zdroj: |
Heredity; Feb2003, Vol. 90 Issue 2, p122, 8p |
| Abstrakt: |
Genotypes of high (H[sup m]) and low (L[sup m]) male B transmission rate (B-TR) were obtained. B-TR segregation in the F2 is reported, showing that the H[sup m] and L[sup m] lines differ in a single locus we call mBt (male B transmission), controlling B preferential fertilisation in maize. The egg cells control which one of the sperm nuclei is going to fertilise them, mBt[sup h] egg cells being preferentially fertilised by the sperm nucleus carrying the supernumerary B chromosomes (Bs). It is hypothesised that the mBt gene is involved in the normal fertilisation of maize but the parasitic Bs take advantage of the mBt[sup h] allele to increase their own transmission. Selection was also carried out when the Bs were transmitted on the female side (H[sup f] and L[sup f] lines). The F1 hybrids show that the gene(s) that we call fBt (female B transmission), controlling female B-TR, is located on the A chromosomes acting at diploid level, the fBt[sup l] allele(s) for low transmission being dominant. This allele causes the loss of Bs at meiosis, which is shown using a specific B molecular probe to determine B presence/absence in microspores of both lines and hybrids. Maize Bs are a nice example of intragenome conflict, because the mBt and fBt loci are a polymorphic system of attack and defence between A and B chromosomes. [ABSTRACT FROM AUTHOR] |
| Databáze: |
Complementary Index |
| Externí odkaz: |
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