Mitochondria research in racehorses & other abstracts

[vineyridge]

This is an absolutely fascinating article. Now for the sport horse world to do the same with their horses. Mitochondria wouldn't be affected by breed considerations as much as nuclear DNA.

http://thoroughbredgenetics.com/PACEMAKER%20BG.PDF
Pub Med cite:
http://www.ncbi.nlm.nih.gov/pubmed/16516561?ordinalpos=1&itool=EntrezSystem2.PEntrez.Pubmed.Pubmed_ResultsP anel.Pubmed_SingleItemSupl.Pubmed_Discovery_RA&linkpos=1&log$=relatedarticles&logdbfrom=pubmed

Another article that y'all will find interesting, since the research found no connection between high prices for stud fees and results in performance with race horses.
http://www.ncbi.nlm.nih.gov/pubmed/18089517?ordinalpos=1&itool=EntrezSystem2.PEntrez.Pubmed.Pubmed_ResultsP anel.Pubmed_SingleItemSupl.Pubmed_Discovery_PMC&linkpos=1&log$=citedinpmcarticles&logdbfrom=pubmed

Genetic parameters of event horse breeding;
http://www.ncbi.nlm.nih.gov/pubmed/11333833?ordinalpos=1&itool=EntrezSystem2.PEntrez.Pubmed.Pubmed_ResultsP anel.Pubmed_SingleItemSupl.Pubmed_Discovery_RA&linkpos=1&log$=relatedarticles&logdbfrom=pubmed

I have this whole article, thanks to a CoTHer, and have passed it on to a few of you.

Breeding to chasers for jumping ability:
http://www.ncbi.nlm.nih.gov/pubmed/17550353?ordinalpos=1&itool=EntrezSystem2.PEntrez.Pubmed.Pubmed_ResultsP anel.Pubmed_SingleItemSupl.Pubmed_Discovery_RA&linkpos=1&log$=relatedarticles&logdbfrom=pubmed

[Jenny Jones]

A brilliant site! How do you go about accessing the whole articles; I suppose you join and buy them, but can an individual rather than an organisation do this?

I once saw a great article about a piece of research which suggested that as much racing success was had by the offspring of apparently low class horses as the offspring of apparently high class horses; I am being vague here as I can't remember the parameters used or what exactly they factored in; however, there are of course many more low class horses so on a horse by horse basis success was less likely. Encouraging, though, to think that it wasn't impossible to breed a top class horse from an "ordinary" mare. I lost the article and I've been keeping an eye out for that research ever since; I wonder if it might be on that site?

[vineyridge]

Some of the publications who participate in PubMed, especially US and Canadian ones, have the full articles on file there. Others just file the abstracts, and for those one hopes to cultivate friends in universities who can access the articles through the university subscriptions. :)

PubMed IS a brilliant site, and one of the best things around. However, if you know the title of the article, sometimes it will appear during a google search. There is a journal which is entirely free and publishes the full papers which is called PLos ONE, http://www.plosone.org/home.action, and the full text of the Hill et all research on TB genetic distance preferences can be found there. That's the recently published paper on the CC, CT, TT alleles on the myostatin chromosome. It's a fun place for science geeks.

Just found an intriguing new article on In Vitro fertilization in mice ( http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0009218 ) with the following conclusion--

Abstract

Assisted Reproductive Technologies (ART) are increasingly used in humans; however, their impact is now questioned. At blastocyst stage, the trophectoderm is directly in contact with an artificial medium environment, which can impact placental development. This study was designed to carry out an in-depth analysis of the placental transcriptome after ART in mice.
Methodology/Principal Findings

Blastocysts were transferred either (1) after in vivo fertilization and development (control group) or (2) after in vitro fertilization and embryo culture. Placentas were then analyzed at E10.5. Six percent of transcripts were altered at the two-fold threshold in placentas of manipulated embryos, 2/3 of transcripts being down-regulated. Strikingly, the X-chromosome harbors 11% of altered genes, 2/3 being induced. Imprinted genes were modified similarly to the X. Promoter composition analysis indicates that FOXA transcription factors may be involved in the transcriptional deregulations.

Conclusions

For the first time, our study shows that in vitro fertilization associated with embryo culture strongly modify the placental expression profile, long after embryo manipulations, meaning that the stress of artificial environment is memorized after implantation. Expression of X and imprinted genes is also greatly modulated probably to adapt to adverse conditions. Our results highlight the importance of studying human placentas from ART.

Found this older article on TB adaptation for high performance, also with Hill as one of the authors.
http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0005767
Abstract Top

Thoroughbred horses have been selected for exceptional racing performance resulting in system-wide structural and functional adaptations contributing to elite athletic phenotypes. Because selection has been recent and intense in a closed population that stems from a small number of founder animals Thoroughbreds represent a unique population within which to identify genomic contributions to exercise-related traits. Employing a population genetics-based hitchhiking mapping approach we performed a genome scan using 394 autosomal and X chromosome microsatellite loci and identified positively selected loci in the extreme tail-ends of the empirical distributions for (1) deviations from expected heterozygosity (Ewens-Watterson test) in Thoroughbred (n = 112) and (2) global differentiation among four geographically diverse horse populations (FST). We found positively selected genomic regions in Thoroughbred enriched for phosphoinositide-mediated signalling (3.2-fold enrichment; P<0.01), insulin receptor signalling (5.0-fold enrichment; P<0.01) and lipid transport (2.2-fold enrichment; P<0.05) genes. We found a significant overrepresentation of sarcoglycan complex (11.1-fold enrichment; P<0.05) and focal adhesion pathway (1.9-fold enrichment; P<0.01) genes highlighting the role for muscle strength and integrity in the Thoroughbred athletic phenotype. We report for the first time candidate athletic-performance genes within regions targeted by selection in Thoroughbred horses that are principally responsible for fatty acid oxidation, increased insulin sensitivity and muscle strength: ACSS1 (acyl-CoA synthetase short-chain family member 1), ACTA1 (actin, alpha 1, skeletal muscle), ACTN2 (actinin, alpha 2), ADHFE1 (alcohol dehydrogenase, iron containing, 1), MTFR1 (mitochondrial fission regulator 1), PDK4 (pyruvate dehydrogenase kinase, isozyme 4) and TNC (tenascin C). Understanding the genetic basis for exercise adaptation will be crucial for the identification of genes within the complex molecular networks underlying obesity and its consequential pathologies, such as type 2 diabetes. Therefore, we propose Thoroughbred as a novel in vivo large animal model for understanding molecular protection against metabolic disease.

Citation: Gu J, Orr N, Park SD, Katz LM, Sulimova G, et al. (2009) A Genome Scan for Positive Selection in Thoroughbred Horses. PLoS ONE 4(6): e5767. doi:10.1371/journal.pone.0005767

Editor: Cecile Fairhead, Pasteur Institute, France

[Jenny Jones]

Vineyridge, sorry not to get back sooner; though I have to pick my way carefully through them word by word, I am loving these articles; this is indeed geek's heaven! I wish I knew enough to get the full picture here.

So; in vitro has some modifying effect at a genetic level; that is on the placenta? but what is the knock-on effect on the embryo? What are the real life implications, do you think?

The article about the modifications to the TB resulting from being bred to race makes me wonder if this is why warmblood breeders have to keep returning to the TB despite its being "designed" for quite a different discipline; those mods could give some competitive advantage in other disciplines but would never develop or be maintained sufficiently except in the furnace of racing where the horse's physicality is more important (I think) than rider skill. Strength to weight ratio springs to mind; I would expect this to be at its best in the TB. (You can see I like TBs . Even though one kicked me today.)

[sniplover]

I'm happy to get them for you anytime, Viney, anytime. :)