The B chromosome of maize

Carlson, Wayne R.; Phillips, Ronald L.

doi:10.1080/07352688609382210

Cited by 77 publications

(45 citation statements)

References 43 publications

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“…Preferential fertilization also occurs in maize, in which the sperm cell containing one extra set of B-chromosomes fuses with the egg up to 75% of the time (Roman, 1948;Carlson, 1969Carlson, , 1986, but the result is interestingly variable. Rather than simply providing a marker for the sperm cell destined to fuse with the egg, B-chromosomes appear to confer a selective advantage to the sperm cell that contains them (Carlson, 1969).…”

Section: Preferential Fertilizationmentioning

confidence: 99%

Experimental Analysis of the Fertilization Process

Weterings

Russell

2004

THE PLANT CELL ONLINE

165

130

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Section: Preferential Fertilizationmentioning

confidence: 99%

Experimental Analysis of the Fertilization Process

Weterings

Russell

2004

THE PLANT CELL ONLINE

165

130

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“…B chromosomes' origin and maintenance in natural populations have been a matter of debate over the past 50 years (Blackwood 1956;Jones and Rees 1982;Carlson 1986;Porter and Rayburn 1990;Carlson and Roseman 1992;Jones 1995). According to the most recent views, these are selfish genetic elements that are derived from the A complement and that maintain their polymorphism by a series of accumulation mechanisms (e.g., mitotic nondisjunction, reduction of meiotic loss) or, much more rarely, by providing their carriers a selective advantage.…”

mentioning

confidence: 99%

B Chromosome Polymorphism in Maize Landraces: Adaptivevs. Demographic Hypothesis of Clinal Variation

2007

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Cytogenetic analysis of maize landraces from northwestern Argentina has revealed an altitudinal cline in the mean number of B chromosomes (B's) per plant, with cultivars growing at higher altitudes exhibiting a higher number of B's. Altitudinal and longitudinal clines are frequently interpreted as evidence of selection, however, they can also be produced by the interplay between drift and spatially restricted gene flow or by admixture between previously isolated populations that have come into secondary contact. Here, we test the adaptive significance of the observed altitudinal gradient by comparing the levels of differentiation in the mean number of B's to those obtained from 18 selectively neutral loci ½simple sequence repeats (SSRs) among seven populations of the cline. The adequacy of alternative genetic-differentiation measures was determined, and associations between cytogenetic, genetic, and altitudinal distances were assessed by means of matrix-correspondence tests. No evidence for association between pairwise F ST and altitudinal distance or B-chromosome differentiation was found. The contrasting pattern of altitudinal divergence between the mean number of B's per plant and the genetic differentiation at SSR loci indicates that demographic processes cannot account for the observed levels of divergence in the mean number of B's.

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“…The translocation breakpoint is 3.0-cM proximal to the R locus. The B centromere is known for its propensity to nondisjoin at the second pollen mitosis, causing the two sperm nuclei to differ in their genetic constitution (Carlson 1986). In a cross where a male TB-10L32 heterozygote is crossed to an Ab10-I female, the progeny will be N10/Ab10-I (normal, euploid), N10/N10/Ab10-I (hyperploid), and (À)/Ab10-I (hypoploid).…”

Section: Resultsmentioning

confidence: 99%

The Maize Ab10 Meiotic Drive System Maps to Supernumerary Sequences in a Large Complex Haplotype

Mroczek

Melo²,

Luce³

et al. 2006

Genetics

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The meiotic drive system on maize abnormal chromosome 10 (Ab10) is contained within a terminal domain of chromatin that extends the long arm of Ab10 to $1.3 times the size of normal chromosome 10L. Ab10 type I (Ab10-I) does not recombine with normal chromosome 10 (N10) over an $32-cM terminal region of the long arm. Comparative RFLP mapping demonstrates that multiple independent rearrangements are responsible for the current organization of Ab10-I, including a set of nested inversions and at least one long supernumerary segment at the end of the chromosome. Four major meiotic drive functions, i.e., the recombination effect, smd3, 180-bp neocentromere activity, and the distal tip function, all map to the distal supernumerary segment. TR-1-mediated neocentromere activity (the fifth known drive function) is nonessential in the type II variant of Ab10 and maps to a central region that may include a second supernumerary insertion. Both neocentromere activity and the recombination effect behave as dominant gain-of-function mutations, consistent with the view that meiotic drive involves new or alien gene products. These and other data suggest that the Ab10 meiotic drive system was initially acquired from a related species and that a complex haplotype evolved around it.

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The B chromosome of maize

Cited by 77 publications

References 43 publications

Experimental Analysis of the Fertilization Process

Experimental Analysis of the Fertilization Process

B Chromosome Polymorphism in Maize Landraces: Adaptivevs. Demographic Hypothesis of Clinal Variation

The Maize Ab10 Meiotic Drive System Maps to Supernumerary Sequences in a Large Complex Haplotype

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