Talk:Chromosomal crossover

message: Someone needs to disambiguate this. KirbyMeister 01:36, 10 May 2004 (UTC)
thread_title:  Disambiguation 

message: The Idea of crossing over was first proposed by F.A. Janssens.  Does anybody know anything more about him? Fawcett5 18:17, 17 January 2006 (UTC)
replies: text: Yes, that needs to be changed.  The cytological basis of crossing over (and even the term "crossing-over") was first described by F.A. Janssens.  TH Morgan just used that knowledge to help him expain gene linkage.  Morgan postulated that the crossing over (that Janssens had already discovered) created new chromosomal types in a few gametes. — Preceding unsigned comment added by 132.170.160.178 (talk • contribs) 23:32, 27 January 2007 (UTC)
thread_title:  F. A. Jannsens 

message: This article should probably be merged with / redirect to genetic recombination. Gringer 03:02, 7 July 2006 (UTC)
thread_title:  Merge Proposal 

message: what is its significance
can naybody tell me please —The preceding unsigned comment was added by 203.101.182.58 (talk) 11:28, 27 February 2007 (UTC)
thread_title:  significance of crossing over 

message: This article says the following at the end of its first paragraph: "Chromosomal crossovers also occur in asexual organisms and in somatic cells, since they are important in some forms of DNA repair."  I think this is incorrect.  The journal article being used as a reference for this statement says: "Recombination in somatic cells is rarely associated with crossovers, and crossovers have the potential to generate genomic rearrangements and large-scale loss of heterozygosity (LOH)." (See: ) To my understanding, it is exclusively non-crossover (i.e. gene conversion) products of recombination that result from accurate recombinatorial DNA repair in bacteria and somatic cells in eukaryotes.  I've reworked the lead to give what I think is a more accurate description of the subject; any feedback would be appreciated. Emw (talk) 15:08, 23 October 2009 (UTC)
replies: text: Wouldn't it effect repair simply in the sense that the broken gene is sometimes swapped with a working equivalent, thereby allowing a mechanism for the defective gene to be selected out from the population without also affecting all the surrounding genes? (And moreover, that recombination is intimately involved with the whole concept of maintaining homologous chromosomes, which themselves are a system for surviving damage to one version of a gene?) Even in asexual reproduction, it seems like the same processes would at least have the potential to achieve the same functions. Cesiumfrog (talk) 04:07, 31 December 2010 (UTC)
replies: text:  It sounds like you're referring to homologous recombination that results in non-crossover products, i.e. not chromosomal crossover. Emw (talk) 14:50, 31 December 2010 (UTC)
thread_title:  Possible inaccuracy: "Chromosomal crossover is important in DNA repair" 

message: Several of our biology articles have a somewhat confused mixture of narrowly human and more general biological view points.  I think this goes for the section titled Problems in this article, which now reads:
::Although crossovers typically occur between homologous regions of matching chromosomes, similarities in sequence can result in mismatched alignments. These processes are called unbalanced recombination. Unbalanced recombination is fairly rare compared to normal recombination, but severe problems can arise if a gamete containing unbalanced recombinants becomes part of a zygote. The result can be a local duplication of genes on one chromosome and a deletion of these on the other, a translocation of part of one chromosome onto a different one, or an inversion.
It is true that gene duplication, gene deletion, and gene inversion in general have negative effects for the concerned individuals, and I suppose that therefore unbalanced recombination in a human in general may be considered as a medical problem.  However, in the long run, the much rarer instances when the effects are beneficial have had a rather large positive impact on the evolution of certain lines of organisms.
I think both the negative medical effects and the rare but important positive evolutionary effects should be mentioned here.  I'll make a try at rewriting the section in such a manner. JoergenB (talk) 22:40, 3 December 2013 (UTC)
thread_title:  Not ONLY "problems"! 

message: Substituted at 11:43, 29 April 2016 (UTC)
thread_title:  Assessment comment 

message: (Warning, haven't read article, this ma be a stupid question already answered) Is it known how crossover works with reference to intron/exon boundaries? Jimw338 (talk) 13:03, 26 April 2017 (UTC)
thread_title:  Crossover and intron/exon structure 

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thread_title:  A Commons file used on this page has been nominated for speedy deletion