Saturday, July 2, 2011

Microsatellite ETH10 Genotypes on Bovine Chromosome 5 in British White Cattle

J.West's King Cole,
ETH10 Genotype 217/221

The British White cattle breed has never enjoyed a close investigation of their genetic make-up so far as I know.  Several members of the BWCAA have accomplished DNA testing for a variety of carcass related traits with Pfizer and Igenity the past several years; but those results are animal specific and have not been examined or summarized by a research person or organization.  As well, many British White breeders have established a DNA profile for herd sires that is used for parent testing of their calves.  Those DNA profiles for parent testing currently identify 16 different microsatellite genetic markers of the individual animal.   

J.West's Tom Sawyer, ETH10 Genotype 217/219

Of those 16 different markers, one is referred to as ETH10, and is found in a particular gene on bovine chromosome 5.  That gene is referred to as the STAT6 gene.  The Red Angus study referenced here explores the correlation between certain ETH10 allelic sizes ( range is 199 to 225) and growth rates in cattle. My guess is this ETH10 marker is one of those evaluated by both Pfizer and Igenity when scoring for various carcass traits and potentialities of growth. 

The cattle used in this 2009 study were registered Red Angus, and this study makes reference to a prior one using registered Brangus cattle and correlating carcass yield and quality and birth weights with ETH10 genotypes.  Fortunately, I was able to locate this referenced Brangus study, and both studies are available online at the links provided at the end of this article.

J.West's Mazarati, Owned by Southern Cross Cattle,
ETH10 Genotype 217/217
What caught my attention when reading through the Red Angus study were the allelic sizes (they sounded like familiar numbers) that were correlating with higher 205 day weight, as well as the size or percent of longissimus muscles (LMs) compared to body weight (BW) and the percent of fat in the LMs of the Brangus cattle in the referenced 2008 study.  This 2009 study concluded that Red Angus cattle with both the 217 and 219 genotypes had higher weaning weights:
 ". . . Angus cattle with the 217/219 genotype tended to have 2.1% heavier . . . 205-day weight than other genotypes."  (1)
The Brangus 2008 study effectively correlated the 217/219 genotype (along with all 'large/large' genotypes) with greater carcass yield and quality as well:

The results from ETH10 typing can have a 'large' and 'large' designation; an example would be the 217 (large)/219 (large) genotype mentioned above in regard to the Angus cattle and 205 day weights.  In that instance the animal is heterozygous for the 217 and the 219 alleles.  The ETH10 can also have a homozygous result, such as the pair of 217/217 - another large/large.  In the 2008 Brangus study, allele types of 215 and less were designated 'small' and those 217 and above as 'large, thus 215/217 or 215/219 for example would be 'small/large'.

J.West's W.W. Doc, Owned by Halliburton Farms,
ETH10 Genotype 219/221 - Semen is available and cleared
for export to many countries on this mighty fine bull.
 ". . . cattle with the large/large genotype had approximately 5.1% greater . . . percent fat within LM and more LM per BW (body weight) than cattle with small/large or small/small genotypes."  (2)

BIRTH WEIGHTS & ETH10 GENOTYPES in British White Cattle

The 2008 Brangus study also found indicators for birth weight in the ETH10 genotypes.  It was concluded that 'small/large' genotypes had larger birth weights than animals with the 'large/large' genotype:
"Cattle with small/large genotype had (2%) heavier . . . birth weight than cattle of the large/large genotype . . ." (2)
Over the course of the past several years I've accumulated many DNA profiles on various cattle, both herd sires and females.  A review of those profiles for the presence of particular ETH10 marker types proved interesting.

CRAE215G, ETH10 Genotype 215/221

Of the 35 DNA profiles I have on file -- 23 of the profiles were 'large/large' genotypes, and 12 were 'small/large' genotypes.  Of those 12 'small/large' genotypes, 5 of them have the common ancestral cow, CRAE 215G, who carried the alleles 215/221.  As I have the DNA profile on her sire, Mr. NOY 1B, I can see that the CRAE cow received her 215 allele from her dam, MS NOY 8E, as her sire carried the markers 217/221, so MR NOY couldn't have given her the 'small' 215 allele.  What's notable here is that this CRAE cow did tend to have larger birth weights.  She was also a very big cow, one of the biggest cows I've ever had in pasture here.  I once thought the tendency for higher birth weights was due to her size -- that would appear to perhaps not be the case at all. 

Black Sapphire, ETH10 217/219
 An example of that would be J.West's Black Sapphire.  While she wasn't quite as tall as this CRAE cow, she was for sure as heavy, if not heavier.  Black Sapphire had average to small birth weights, and has the ETH10 alleles of 217/219, or 'large/large' as defined in the Brangus study referenced here.  Coincidentally, her sire was also MR NOY 1B. 

A look at 3 other animals in this group of 12 with the 'small/large' genotype reveals another ancestral clue.  All three of these British Whites track right back to the English bull Woodbastwick Randolph Turpin.  In all three instances it is clear that the dams did not carry the small genotype '215' and thus it was received from the Turpin bull.  While my experience with Turpin calves is limited, I do believe he tends to have larger than average birth weight calves.

But, before you get real negative on the 215 genotype, it is worth noting that the actual best result for Average Daily Gain was found in Red Angus cattle with the 215/217 genotype.  Follow the link below for the study and you'll find a chart on the last page with the actual results for several items, including the 205 day weight of 217/219 genotypes highlighted in the study's conclusions.

Let's jump back to the carcass and growth traits indicated by my little study of these 35 British Whites.  23 of the 35 British Whites have the 'large/large' genotypes, or ~66 %.  While I would like to see that percentage higher, it is still very supportive of the excellent carcass traits of the British White breed when you consider the negative skew from the single family line of CRAE 215G discussed above.

J.West's El Presidente, ETH10 Genotype 217/217
Of particular interest as well in comparing these study results is the high prevalence of allele 217 in this population of 35 British Whites.  The allele 217 was also the most prevalent in the Red Angus population of cattle, with about 75% being either heterozygous or homozygous to this allele.  In this population of 35 British Whites, 24 of them, or 69 %, had the allele 217, and it was as well the most prevalent ETH10 allele of these 35 British Whites. 

Also, the Red Angus study concluded that the best 205 day weights came from animals with the 217/219 pairing of alleles, but only 8.7% of the Red Angus had this pairing.  In this British White population, there are 6 animals with the 217/219 allele pairing, or 17%Of those, three are herd sires -- J.West's Tom Sawyer, J.West's S.S. Carter, and J.West's Blue Boy.  And one of them was a bull we butchered, J.West's Prime Dude, who had the biggest dinner plate ribeye area of any bull we've butchered, and very nice marbling on a grass diet as well.

In the Brangus study the most prevalent alleles (greater than 5%) in the population were 209, 211, 213, 217, 219, and 221.  The only 'small' allele in this British White population was the 215 genotype.   In the Red Angus study the most prevalent alleles were 215, 217, 219, 221, and 223.  In this population of 35 British Whites, 100% of the cattle had one or more of each of the most prevalent Red Angus allele genotypes with the exception of allele type 223.  In the Red Angus population studied there was an ~14% occurrence of the 223 allele. 

The breakdown of all ETH10 allele frequencies in this population of 35 British Whites is as follows:
Allele Type 215 - 34 percent
Allele Type 217 - 69 percent
Allele Type 219 - 31 percent
Allele Type 221 - 31 percent
The breakdown of all ETH10 allele pairings (which were the basis for the Red Angus study) is as follows:

Alleles 215/217 - 7 animals
Alleles 215/219 - 2 animals
Alleles 215/221 - 3 animals
Alleles 217/217 - 6 animals
Alleles 217/219 - 6 animals
Alleles 217/221 - 5 animals
Alleles 219/219 - 1 animal
Alleles 219/221 - 2 animals
Alleles 221/221 - 3 animals
These results indicate a very tight gene pool, or low diversity, for this marker in the British White breed here in the USA.  However, most of the DNA profiles I have on file were necessitated by embryo flushing, artificial insemination, as well as DNA profiling of herd bulls for subsequent parentage confirmation.  The DNA results from parent testing embryo donor cows and their subsequent calves place quite a skew on these results.  They account for 9 (from 2 family groups) of the British Whites in this population of 35. 
J.West's Elvis in 2005, ETH10 Genotype 217/221

It would appear that the greater the size of the ETH10 allele, the greater the marbling potential of a given animal.  But, that is an unscientific observation, merely one of inference from the various studies reviewed.  In the Wagyu breed there is a prevalence of the ETH10 allele 223, which is considered a source of that breeds renowned ability to marble. 
"Barendse (2002) reported an association between marbling score and ETH10 alleles in Wagyu cattle. In brief, the 223 allele was associated with higher marbling scores relative to the 217 allele." (2)

So, if you are a British White breeder out there with some curiosity about the ETH10 allelic markers in your cattle -- have a look.  If in fact your British White has the allele 223 or greater, or different alleles altogether, please be sure and let me know!

Update 7/6/11:  There are in fact family lines of British White cattle that have the 223 size allele at marker ETH10, and those lines include offspring of the full English bull, Woodbastwick Randolph Turpin.

So what is the conclusion here?  That is perhaps a puzzle if I've not succeeded in a clear presentation of the basic premise and results of these studies, and how the DNA data in these studies provides very positive correlation and support to the British White breed's comparable characteristics as to birth weights, carcass yield and quality, and growth rates to that of other desirable  bos taurus beef cattle breeds - such as Angus.  While we cannot fund our own DNA studies, we certainly can make use of studies of other bos taurus breeds originating in the United Kingdom in gaining better understanding of the genetics of the British White breed. 

It is a remarkable thing that we can pull some tail hair or send a straw of semen to a lab and get back 16 identified DNA markers of that animal along with confirmation of their parentage.  Even more interesting is just what can be found beyond parentage confirmation in the details of those specific 16 DNA markers. 
UPDATES 7/9/11: 

(1) The Simmental breed in Poland underwent microsatellite study in 2006, and it is interesting to note on page 4, Table 1 of that study that the ETH10  genotypes were of low diversity, with genotypes 217 and 219 accounting for 92% of all animals studied.  The genotype 217 accounted for 74% of the animals studied; 219 for 18%; 221 for 1.6%; 223 for 3.8% -- along with the 'small' genotye 215 accounting for 1.6%.

(2) The Blanco Orejinegro (BON) Columbian cattle breed has been the subject of DNA microsatellite marker study.  This 2009 study demonstrates that the BON breed  is predominantly the 'large' ETH10 genotypes.  It is interesting to note that none of those ETH10 genotypes are the same as those found in the Red Angus, Brangus, Simmental, or British White.  They are:  218 at 33.8%; 220 at 20.3%; 222 at 25.4%; 224 @11.8%; 226 at 3.3%; and the 'small' alleles of 216 at 3.3% and 214 at 1.6%.  (See March 2011 Blanco Orejinegro blog post for information about this interesting white cattle breed.)
(3) The bos indicus Nellore breed of Brazil, which has many characteristics similar to the bos indicus Brahman breed, has been the subject of DNA microsatellite marker study.  This 2006 study identified the ETH10 genotypes found in the Nellore breed, and they are largely of the 'small' type - including 49.6% with marker 209 and 34.5% with 207.  The Brangus study had a more significant frequency of 'small' type ETH10 markers, including marker 209 at 10%.

(4) Icelandic cattle were examined for microsatellite markers in 2008.  "The Icelandic cattle breed is the only cattle breed in Iceland and has been, more or less, isolated for over 1000 years; therefore it is considered a closed population."  This 2008 study (See Table 6, Page 25) identified the ETH10 genotype frequencies in Icelandic cattle.  The 'large' alleles measured were 217 at 6.6% of the population; 219 at 61.5%;  223 at 14.3%.  The 'small' alleles were 214 at 5.5% of the population, and 215 at 9.3%.

(5) Piedmontese, Maremmana, and Podolica were examined for microsatellite markers in 2003.  See 'Genetic Diversity between Piedmontese, Maremmana, and Podolica Cattle Breeds' .  The allele frequencies are charted in Table 1 .
(6) Fleckvieh, Charolais, and Simmental were examined in a 2010 study of cattle in the Czech Republic.  Utilization of a 17 Microsatellites Set For Bovine Traceability in Czech Cattle Populations .
(7) Bulgarian Grey Cattle were examined in a 2005 study.  Genetic Diversity in Bulgarian Grey Cattle As Revealed By Microsatellite Markers.

Original Studies Reviewed:


De Beauvoir's Huckleberry Finn on the Left with Gerald Fry,
This full English bull is possibly the ETH10 Genotype 217/221 or Homozygous 221/221,
but that's just a guess from looking at his offspring's DNA types.