𝔖 Bobbio Scriptorium
✦   LIBER   ✦

Mammalian meiotic recombination: a reexamination

✍ Scribed by Terry Ashley


Book ID
104664370
Publisher
Springer
Year
1994
Tongue
English
Weight
796 KB
Volume
94
Category
Article
ISSN
0340-6717

No coin nor oath required. For personal study only.

✦ Synopsis


Recombination nodules (RNs) are small electron-dense structures associated with the synaptonemal complex. Two types have been identified: early RNs present during zygonema-early pachynema, which are thought to be involved in gene conversion and synaptic initiation, and late RNs present during mid-to-late pachynema, which are thought to be involved in reciprocal recombination leading to chiasma formation. In organisms as diverse as Sodaria, Drosophila, and plants there is indeed a close correlation between the observed number of late RNs and crossovers, or their cytogenetic manifestation, chiasmata. However, as this reexamination of the human data shows, there is not a similar correlation in mammals. Instead, there is a severe deficiency in RNs in eutherian males and marsupial females near chromosome ends and other recombinational "hot spots" (defined genetically), or "localized chiasmata" (defined cytogenetically). Many of these sites of hyper-recombination correspond to sites of telomere or telomere-associated sequences. Together these observations suggest the possibility of a second, mechanistically different, recombination pathway that does not involve RNs, but may directly involve telomere or telomere-associated sequences. This pathway may be responsible for sex-specific hot-spots of recombination observed at highly localized sites throughout the genome.


πŸ“œ SIMILAR VOLUMES


Mammalian Meiotic Recombination Hot Spot
✍ Arnheim, Norman; Calabrese, Peter; Tiemann-Boege, Irene πŸ“‚ Article πŸ“… 2007 πŸ› Annual Reviews 🌐 English βš– 399 KB
A reexamination of the diploidlike meiot
✍ Ibrahim Jack Mursal; J. E. Endrizzi πŸ“‚ Article πŸ“… 1976 πŸ› Springer 🌐 English βš– 989 KB

Chromosome associations at pachytene, diakinesis, and metaphase I were analyzed in haploids of the allotetraploid G.hirsutwn, in the F1 hybrid between G.arboreum (A2) and G. raimondii (D5), and in the doubled hybrid 2(A2D2) in an effort to define more clearly the mechanism responsible for the diploi