Spontaneous Inversion Heterozygotes in <i>Aloe barbadensis</i> Mill.

Abstract

Summary A population of cultivated Aloe barbadensis Mill. displayed various types of chromosomal configurations at anaphase/telophase-I and II due to inversion heterozgosity. The population was characterized by the presence of bridges and fragments because of various numbers and positions of cross-overs in the inversion loop. The inversion heterozygote had very low pollen fertility.

Spontaneous Inversion Heterozygote in <i>Haworthia limifolia</i>

“…The most obvious genetic effect of inversions is formation of unbalanced gametes that often causes microspore sterility (Wang et al 2008). As is expected, the loss of chromosomal fragment as a result of paracentric inversion leads to deficient gamete and high sterility (Ahirwar and Verma 2013).…”

“…Several workers have found spontaneous inversion heterozygotes in various plant species from natural populations, such as in Aloe barbenensis Mill (Ahirwar and Verma 2013, Kaul 1965, Vig 1968, in Haworthia reinwardtii (Brandham 1974), Haworthia glauca (Riley and Majumdar 2011) and in Paeonia decomposita (Wang et al 2008).…”

Morphological and cytogenetic characterization in experimental hybrid Aloe jucunda Reyn. x Aloe vera (L.) Burm. f. (Asphodelaceae)

“…Additional bridges, fragments, micronuclei, and microspores are frequent in Aloe species with heterozygous paracentric inversions (Riley andMajumdar 1979, Ahirwar andVerma 2013). The pairing between the inverted chromosome and its pachytene homologue must involve the formation of a loop where crossovers occur between homologous chromatids that generate fine chromatin threads linked to two centromeres and totally unlinked fragments of these, causing the loss of genes that reduce the fertility of gametes.…”