Genetic recombination in plants

Repetitive sequence environment distinguishes housekeeping genes

“…Long repeats including LINE-1 elements are normally heavily DNA-methylated (Woodcock et al, 1988;Crowther et al, 1991;Woodcock et al, 1997), a feature of heterochromatin. DNA methylation (and heterochromatin in general) has been reported to suppress homologous recombination (Pàldi et al, 1995;Maloisel and Rossignol, 1998;Schnable et al, 1998;Fu et al, 2002;Yao et al, 2002;Yamada et al, 2004;Myers et al, 2005) as well as transposition (Yoder et al, 1997;Walsh et al, 1998;Hirochika et al, 2000;Robertson, 2001;Bird, 2002;Kato et al, 2003). Accordingly, reports of deletions caused by homologous recombination between LINE-1 elements are rare (Segal et al, 1999) except in cancers (Florl and Schulz, 2003) where LINE-1 elements are frequently hypomethylated (Santourlidis et al, 1999;Takai et al, 2000;Ehrlich, 2002;Carnell and Goodman, 2003;Florl et al, 2004;Roman-Gomez et al, 2005).…”

The effects of trans modifiers and tandem duplications on meiotic recombination in maize

“…According to the double strand break repair (DSBR) model , meiotic recombination initiates with a double strand break (DSB). Fungal, animal and plant chromosomes exhibit regions of recombination hyperactivity, i.e., hot spots, and hypoactivity, i.e., cold spots (reviewed in NACHMAN 2002;PETES 2001;SCHNABLE et al 1998). Consistent with the DSBR model, recombination hot spots in Saccharomyces cerevisiae are clearly associated with DSBs (reviewed in LIGHTEN and GOLDMAN 1995) and these DSB hot spots are not distributed randomly across the yeast genome .…”

“…Recombination hot spots in yeast, as evidenced by high frequencies of DSBs, are not distributed randomly across the genome . In most organisms studied, recombination is suppressed near centromeres and, with the exception of C. elegans (BARNES et al 1995), rates of recombination are often positively correlated with gene density (reviewed in LIGHTEN and GOLDMAN 1995;SCHNABLE et al 1998). Recombination events cluster in gene-rich regions in the grasses (Fu et al 2001;GILL et al 1996a;GILL et al 1996b;KUNZEL et al 2000) suggesting that genes are recombination hot spots.…”

“…In addition, sequence polymorphisms (e.g., insertion/deletion and single nucleotide polymorphisms) can greatly reduce the frequency of recombination in both plants and animals (reviewed in SCHNABLE et al 1998;SCHOFIELD and HSIEH 2003). Cis factors (e.g., insertion/deletions) polymorphic among several teosinte and maize al-sh2 intervals significantly affect recombination rates and the distribution of recombination breakpoints across the al-sh2…”

“…Genes are recombination hotspots in bacteria, fungi, plants and animals (reviewed by SCHNABLE et al 1998). For example, the ratio between genetic and physical distances within the maize al gene is 6.25 cM/Mb (CIVARDI et al 1994), as compared to the genome average of 2.4 cM/Mb, a figure that is based on a maize genetic map that consists of 5917 cM (LEE et al 2002).…”