An Inversion in Barley

Cytogenetic mapping with centromeric bacterial artificial chromosomes contigs shows that this recombination‐poor region comprises more than half of barley chromosome 3H

“…Unequal distribution of recombination frequency along the chromosome is the main reason for non‐linear translation of genetic distance into physical distances, hence short genetic distances may translate into shorter or longer physical distances depending on the chromosomal region. Suppressed recombination in the centromeric region is a typical feature for large‐genome Triticeae (Hordeae) species, first observed for barley (Holm, ), followed by similar results for wheat (Dvorak and Chen, ; Gill and Gill, ) and rye (Wang et al ., ). Similar discrepancies between genetic and physical maps have been earlier reported for barley (Karafiátová et al ., ) as well as for other plant species such as maize (Lamb et al ., ), cucumber (Yang et al ., ) and tomato (Shearer et al ., ) underling the importance of cytogenetic confirmation of genetic maps.…”

Cytological Studies on an Inversion in Barley

“…Bridges and fragments in anaphases I and 11 could also be a result of a duplication large enough to allow for chiasma formation. However, no appreciable change in size of any of the chromosomes was seen by HOLM (1960) in this material.…”

“…This X-ray-induced paracentric inversion-heterozygous stock has been previously described (HOLM, 1960;POWELL and NILAN, 1963). Bridges and fragments in anaphases I and 11 could also be a result of a duplication large enough to allow for chiasma formation.…”

“…Only few inversions are known in barley (SMITH, 1941;HOLM, 1960). However, 396 translocation break points were reported (HAGBERG, A. and HAGBERG, G., 1967).…”

Meiotic Investigations in Pinus Silvestris (L)

“…In very few cells, there were one to three bridges, with or without fragments, but with one undviided chromosome remaining in the centre ( Fig. 18; see HOLM, 1960).…”