Talk:Quantitative trait locus

message: I am quite confused with this statement: Unlike monogenic traits, polygenic traits do not follow patterns of Mendelian inheritance (qualitative traits)because in some websites it states the following:
These traits are controlled by multiple genes, each segregating according to Mendel's laws. These traits can also be affected by the environment to varying degrees. 
Copyright © 1998. Phillip McClean
from http://www.ndsu.edu/instruct/mcclean/plsc731/quant/quant1.htm
Please clarify. Thank you
00
::The number of genes involved and the way they interact (with each other and with the environment) to elicit a phenotype is complex and appears non-Mendelian. Alleles of each of the genes that affect the trait segregate and assort independently according to Mendel's laws, but the trait -- the visible manifestation or phenotype -- is not observed to fall neatly into classes with ratios predicted by Mendel's laws, so the inheritance pattern of the trait appears non-Mendelian. Dr d12 04:18, 2 May 2007 (UTC)
thread_title:  Mendelian inheritance 

message: The sentence "The QTL techniques were developed in the late 1980s and can be performed on inbred strains of any species" is very confused.  In fact, this entire article seems to think that interval mapping is the same as QTL analysis, which is not the case (although this is the common usage today).
First off, "QTL techniques" were around well before the late 1980s.  The first example I know of QTL analysis is from Thoday in the 60s and 70s (see Genetics and Analysis of Quantitative Traits by Lynch and Walsh) -- and there were even chromosomal association studies before that in Drosophila [actually, at 3am I discovered "The association of size differences with seed-coat pattern and pigmentation in Phaseolus vulgaris", Sax K, Genetics 140:201-206].  Between Thoday and Lander and Botstein (see later), QTL analysis got a lot more sophisticated, with more sophisticated marker genotyping methods.  The problem with these methods is that while they could detect a QTL, they couldn't tell you where it was (as far as I know).
In the late 1980s Lander and Botstein proposed a new way to use dense markers (in their case, RFLPs, or restriction fragment length polymorphisms).  In their method, pairs of flanking markers are used to estimate the likelihood that a QTL exists at every position in the genome.  This is how the LOD maps are generated (the pretty images in this article).
So, some advice I have for this article:
* Add in some history of QTL analysis that includes Thoday and the many others after him and before Lander and Botstein.
* Have a better explanation of the statistics behind interval/LOD mapping (what this article calls "QTL mapping").  I.e., an LOD score is the log of the ratio between the maximum likelihood that the data fit a null hypothesis and the maximum likelihood that the data fit a QTL hypothesis, given the observed phenotypes and marker genotypes (see Lander and Botstein, "Mapping Mendelian Factors Underlying Quantitative Traits Using RFLP Linkage Maps", 1989).
* Fix the error that QTL mapping can only be performed in inbred strains.  If this were the case we wouldn't have QTL maps for human traits (like osteoporosis, the example in the article).  What's required is linkage disequilibrium between a QTL and a marker (since, if the traits were in Hardy-Weinberg, there would be no association between a marker genotype and a QTL genotype), which is maximized in inbred strains but can also be achieved in the wild, by examining drift-caused disequilibrium in families or expanding populations.
-- Josh 06:57, 7 March 2007 (UTC)
thread_title: History and confusion

message: I am suggesting to merge both candidate gene and polygenic inheritance into this article, since 
#neither article goes beyond the remit of a dictionary entry
#the candidate gene approach is an integral and exclusive part to trait mapping exercises, of which QTL mapping is the more general and powerful version
#it is intellectually more elegant and leads to a better understanding to accommodate polygenic inheritance within a quantitative/discrete/threshold trait framework (oh dear, this one may be controversial...)
Your thoughts? - Samsara contrib talk 18:36, 15 February 2006 (UTC)
replies: text: Candidate gene approach can be the same as QTL, but can leave QTL's out of the picture as well. So, leave than one out.  polygenic inheritance and Quantitatve trait gene should come here. --KimvdLinde 18:43, 15 February 2006 (UTC)
thread_title:  Suggested merges 

message: After several merges, this article is no longer exclusively about QTLs. Rather, it includes all aspects of quantitative inheritance, including QTLs. Thus, I believe a better name for this article would be "Quantitative inheritance" or "Quantitative traits." QTL could then redirect to here. - Raetzsch 17:47, 10 December 2006 (UTC)
thread_title:  Rename article 

message: This page is the destination of redirection for the word "polygenetic" for wiki links of that word from other articles, which use the word in its common English usage of "origin from more than one source" and which have no association with genetics. Please fix this redirection to avoid such pages coming to this page in error. I do not know enough about genetics to be confident enough to fix it myself (e.g. I'm not sure if a redirection from "polygenic" rather than "polygenetic" was the intention).  GeoWriter 14:33, 1 August 2007 (UTC)
thread_title:  Faulty redirection of "polygenetic" - Please fix 

message: The comments on "Intelligence" should be removed. The definition of "Intelligence" has nothing to do with "Quantitative Trait Locus". I'm sure a separate article on the "Genetics of Intelligence" would be of great interest.   —Preceding unsigned comment added by 24.60.239.250 (talk) 23:58, 19 October 2007 (UTC)
replies: text: The article simply says that "some authors include intelligence" as a multifactorial trait, and then explains the definitional problems in doing so. The statements are cited with credible sources. It doesn't declare anything about intelligence to be fact in relation to QTL. Where is the problem? Ward3001 01:45, 20 October 2007 (UTC)
replies: text: If you're serious about it, you can look up the work of Robert Plomin on the heritability of intelligence - or you can read any one of the many books by Deary, Jensen, Eysenck, Brody, or Carroll.  —Preceding unsigned comment added by 24.60.239.250 (talk) 21:19, 21 October 2007 (UTC)
replies: text: I've read those authors, but I don't think you get my point. You say that the "comments on 'Intelligence' should be removed", yet the comments do not express a point of view, they are not unverified, and they are not original research. The comments just state that "some authors include intelligence" within the concept of QTL without stating that intelligence should or should not be included. I don't see a problem. Why should the comments be removed? Ward3001 21:46, 21 October 2007 (UTC)
thread_title:  Intelligence 

message: I added a link to Hip dysplasia (human). There is no page for "congenital dislocation", but the subject is covered on the page I linked.  In the long run you might want to consider taking that out of the "congenital" list.--Lisa4edit (talk) 15:20, 25 April 2008 (UTC)
thread_title:  Hip dysplasia 

message: You may find it helpful while reading or editing articles to look at a bibliography of  Anthropology and Human Biology Citations, posted for the use of all Wikipedians who have occasion to edit articles on human genetics and related issues. I happen to have circulating access to a huge academic research library system at a university with an active research program in these issues (and to other academic libraries in the same large metropolitan area) and have been researching these issues sporadically since 1989. You are welcome to use these citations for your own research. You can help other Wikipedians by  suggesting new sources through comments on that page. It will be extremely helpful for articles on human genetics to edit them according to the  Wikipedia standards for reliable sources for medicine-related articles, as it is important to get these issues as well verified as possible. -- WeijiBaikeBianji (talk, how I edit) 16:52, 11 September 2013 (UTC)
thread_title:  Citations list useful for updating this article 

message: Hello fellow Wikipedians,
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thread_title:  External links modified 

message: The difference seems important between Locus and Loci. One is singular and the other one is plural. Quantitative trait locus would mean that there is only one region contributing to the quantitative aspect of a trait. In the case of a single locus, wouldn't it be a Mendelian inherited trait? 
For QTL studies, we are generally interested in knowing the outlier loci; the ones loci that contains genetic markers (such as SNPs, microsatellites, etc.), contributing the most to determine the variation of a phenotype.  
"Quantitative trait loci (QTL): regions of the genome that contribute to differences in phenotypic traits"
Source: Hendry, A. P. 2016. Eco-evolutionary Dynamics. Princeton University Press.  — Preceding unsigned comment added by Beausoleilmo (talk • contribs) 17:33, 30 November 2016 (UTC)
thread_title:  Locus or Loci