The third in a three-part series

Part I:  our 2008 AI lambs, posted March 10, 2011

Part II:  our 2009 AI lambs, posted March 12, 2011

If you’ve been here recently, you know I  talked at length about the increased variety of coat color and pattern in British Soay sheep as a result of bringing in new genes via artificial insemination starting with the 2007-2008 lamb crop.  Last year, our 2010 lambs included several AI grandlambs and sure enough, the color fun continued.  Our light phase Mustard son (Dean) from the first year of AI served as one of our six breeding rams. I think I mentioned in the earlier color posts that as a lamb, Dean was a typical light phase Soay and he still is as an adult:

Dean, age 2 (Mustard son)

We hoped Dean would produce some pretty light phase lambs for us, and he did not disappoint.  First up, his twins out of Buttermere.

Hepworth & her twin brother Fouldon (Mustard grandchildren)

Next up, Ellerbeck x Dean twins,  another lovely light phase ewe lamb and … and …

Blakeney & her twin brother Barwick (Mustard grandchildren)

You may be asking yourself, “wait a minute, Dean is light phase.  Where did that dark charcoal son come from?”  Well, remember his grandsire, Mustard, carries the gene for self-coloration, and we know that whatever form of “self” came over with Mustard, it expressed itself in Buckley in 2009 and then Barwick in 2010. Are these four lambs the sweetest-looking Soay you’ve ever seen? Wow.

Since I have focused so far on the contributions made by the sires, it is only fair to point out that the mother of tan Hepworth and Fouldon is a plain brown ewe with extensive white spotting — Buttermere — but she is a carrier for light phase.  And so is the mother of tan Blakeney and charcoal Barwick, a plain brown ewe (Ellerbeck) with white spotting, carrier for light phase.  Isn’t color genetics fun?

Dean kept producing interesting colors for us right through the end of lambing last year. Remember our pretty black ewe Heywood from the 2009 lamb crop, daughter of Xanthoria, a plain brown ewe, and Curtis,the dark charcoal son of  Norris?  Last year we bred Xanthoria to Dean and what should appear but another black lamb.

Cley, age 7 weeks, Mustard granddaughter

Cley, age 3 months

Cley, age 6 months

There’s a video of Cley the day she was born if you’re interested in seeing how totally black she was when she came out.  She has the same unusual eye “ring” we saw in Cantrall and Buckley the year before, and the same white “dot” on her lip (but this time on her right lip) that we saw in Heywood.  But Heywood is out of Norris, and Cley is out of Mustard.  What’s going on here?  Genetic diversity at work!

One of the most intriguing parts about all this new color is what role the ewes play in the transmission of colors and patterns to their offspring.  Here is another picture of Xanthoria, mother of two black ewe lambs (so far), one a granddaughter of light phase Mustard, and one a granddaughter of brown Norris:

Xanthoria, mother of Heywood & Cley

Too bad you can’t see Xanthoria’s white belly and dark legs in this picture – typical British pattern and markings.  She was described as “very dark brown with black legs” as a lamb, so she must contribute color genetics to her black lambs.  But look back at the picture of her with Heywood.  Who knew she would throw black lambs?

Remember Keverne’s triplets from the 2009 lamb crop, the black/tan/chocolate trio? Look back at Keverne in the picture of her triplets; she also is a plain brown ewe with a white belly and white triangular eye markings.  Nonetheless, two years running she produced a light-phase lamb with eye rings, first Cantrall in 2009, and then Westerfield in 2010.  Here’s Westerfield:

Westerfield, age 10 weeks, Mustard grandson

Westerfield never was as “chocolatey” as Cantrall, and Westerfield’s eye rings faded as he matured, leaving him looking much more like a conventional light phase British Soay sheep.

Last year (2010 lamb crop) we also used a Norris son, Glen, as one of our breeders. His lambs are not as distinctive in color as the lambs out of Dean, but at least one of Glen’s offspring, a pretty ewe named Mattishall, shows some of the darker color we first saw in Norris’ daughter Vieva and his son Curtis, Glen’s father:

Mattishall, age 5 months, Norris granddaughter

I need to circle back to something I said much earlier in this group of posts:  our Norris and Mustard progeny and grandlambs are by no means all new colors.  In fact, our last lamb in 2010 came out a textbook mouflon brown, but as you can see, her “common” coloring slows her down not one bit:

Yarmouth, age 5 weeks, Norris granddaughter

Hmm, Yarmouth’s legs look pretty dark in this picture, don’t they?  I need to get back out into the gimmers’ pasture and see how her legs and face look by now.  Maybe she has some of the darker coloring from her grandsire after all.

It’s no secret that a lot of the lambs from the AI project, both generations, remain on our farm.  What else would you expect from a geneticist?  But we have sent AI grandlambs to new homes in seven states and British Columbia (so far) and we expect these ambassadors of diversity to contribute to the important work of genetic conservation and preservation in the flock throughout North America.

With 2011 lambing set to begin this week, who knows what new color adventures await us and where they will end up?  Stay tuned.

For now …

The second in a three-part series

Part I:  our 2008 AI lambs, posted on March 10, 2011

Part III:  more new colors in our 2010 lambs, posted on March 14, 2011

Once Norris sired two uniform dark charcoal British Soay lambs in 2008, we figured that was it for new colors and patterns from the  AI project.  Wrong!  Spring 2009 brought more color surprises.

First came triplets, just like last year, this time from Keverne by Mustard.  But instead of three tan lambs (remember Mustard is light phase) or three plain brown lambs (Keverne is plain brown), out popped a black, a tan, and a chocolate, a veritable Soay rainbow!

AI triplets Cantrall, Buckley & Dora at age 12 days

Dora’s face shows some of the ash-grey look even though she is light phase, but it is subtle and I can’t seem to capture it on film.  Not so with Buckley and Cantrall.  There is nothing nuanced about their fleece color or their patterns.

Buckley remains nearly solid black, but he also shows a new eye marking pattern, almost like a bull’s eye around each eye.

AI ram lamb Buckley at age 6 days

Buckley at age 2 months

Stud muffin Buckley at age 13 months

As if Buckley’s distinctive coat coloring were not enough, when Steve up-ended him last summer to trim his hooves, we were presented with two gleaming, nearly-white balls.  Buckley no doubt was trying to say to Steve, “the better to see ewes with, my dear.”

Buckley shows off his wares

Side note: for readers over the age of 50 or so, do you remember Buckminster Fuller and Bucky Balls?

Okay, back to business.  Milk-chocolate triplet Cantrall is neither typical mouflon nor the classic self-colored light pattern often referred to as “moorit.”  His pattern reminded us of Vieva and Curtis in 2008, but from the light phase rather than the dark phase alternative.  Cantrall’s distinguishing features from day one and as he matured were the unusual “ring” around his eyes, like Buckley’s, and a somewhat muted greyish brown fleece, as though someone rubbed his face lightly with ashes. We began to see a pattern in the new pattern.

AI ram lamb Cantrall at age 6 days

Cantrall at age 6 weeks

Cantrall at age 10 months

The ash-brushed face effect showed up again more prominently in our fetching little ewe Tylesley, daughter of Borrowby x Curtis (son of Norris). We laughed every time we saw her as a lamb. She looked as though she was fixing to run away and join the circus clowns.  But Tylesley soon morphed into an elegant grey ewe with long horns in addition to her ash-grey face.

AI ewe lamb Tylesley at age 6 days

Tylesley at age 4 months

Tylesley at age 18 months

Our 2009 lambing season ended, or so we thought, with the arrival of Kiger’s conventionally-bred ram lamb on May 8, 2009. We particularly regretted that Xanthoria did not lamb, since we we were short on ewe lambs and hoped for another Curtis daughter as interesting as Tylesley.  Nearly a month later, on June 3rd, well after we had closed up shop on lambing and on the last possible day a lamb could arrive (148 days after Curtis returned to the bullpen), I sat in the kitchen with my morning coffee when my walkie-talkie crackled with Steve’s excited voice:

“Are you sitting down?”

“Yes.”

“Xanthoria lambed, looks like about 4:00 a.m.”

“Really?  Is it another ram?”

“No, it’s a ewe lamb.”

“Terrific!”

“Are you still sitting down?”

“Yes, why?”

“She’s pitch black, just like an ink well, no shades of grey this time, just black.”

Wow. Look at what Steve found that morning:

AI granddaughter Heywood on day 1

Heywood remains almost solid black to this day.  When we examined her closely as a lamb, we observed 10-20 little white hairs around her nipple buds, and we wondered whether that hint of non-self-coloration would spread. It has, and now when we up-end Heywood we find a fair amount of somewhat lighter charcoal-colored fleece on her belly and some off-white fleece around her mouth.  I cannot attach genetic significance to anything, much less these new colors and patterns, and Steve is still poring over his library of articles and musty textbooks to see if these not-quite-black Soay fall into known categories.  For now, we describe the appearance of Vieva, Curtis, and Heywood as uniform dark charcoal to reflect both the fact that they are not mouflon and they are not classically self-colored black.   In the following pictures, you will see Heywood begin to take on just a hint of lighter fleece around her mouth and elsewhere.

Heywood at age 3 weeks

Heywood, age 4 weeks

She remained solid black throughout her first summer and fall:

Heywood at age 10 weeks

Heywood at age 4 months

By the time she was a year old, Heywood developed her most unique feature: a small white “dot” on her lower left lip, much like her sire Curtis. Although her fleece bleached out a lot last summer, she is still solid black at the base of her fleece, other than on her back end and parts of her belly:

Heywood at age 15 months with white mouth spot

Heywood at age 16 months with sun-bleached fleece

I have nothing profound to say about the next picture, but it is one of my favorites for showing off color variety. Heywood on the left, and on the right is light phase Arzie, twin of Dean  and daughter of Mustard:

Heywood & Arzie at age 18 months

At the conclusion of 2009 lambing, we decided to take a break from the complexities of artificial insemination and do all our breeding in fall 2009 with six of our on-site rams, including Glen (Vieva’s twin and a Norris son) and Dean (Arzie’s twin and a Mustard son). We weren’t sure we would get any more color surprises using AI sons rather than the donor rams’ sperm, but we thought we might, since we already had Tylesley from AI son Curtis. Our rams did not disappoint. For the 2010 color story, stay tuned.

For now …

The first in a three-part series

Part II: more new colors in our 2009 AI lambs, posted March 12, 2011

Part III: more new colors in our 2010 lambs, posted March 14, 2011

In the last three years, the color palette of British Soay sheep in the United States and Canada has expanded dramatically.  Looking back, it is apparent that much of the variety of color and pattern seen in the ancestral Soay of St. Kilda was not represented in the six Soay sheep that emigrated to Quebec in 1990.  It was not until artificial insemination (AI) began in 2008 on our farm and on Kathie Miller’s farm that at least some of these “missing” genes came to be represented in the full Soay sheep in North America.

Genetic diversity in action: our 2010 British Soay lambs

The growing range and nuance in fleece color mark an intriguing new chapter in the life story of these sheep.  There is no better way to “talk” about the new colors than through pictures.  But first … a bit of historical and genetic context.

From 1990, when the first Soay lambs (Nougat and Carob) were born on George Berci’s farm near Montreal, until 2008, all the descendants of the original six founders looked pretty much alike:  brown fleece, white belly, sometimes a triangular white eye marking, sometimes darker legs, and occasionally a tan or white-spotted animal.  This homogeneity is not surprising, since five of the six founders– Maple, Butternut, Lily, Walnut, and Augustus — derived from a single flock in England and were substantially interrelated. Within that flock, where cousins bred to cousins, nieces to uncles, and so forth, there developed strong family resemblances, as illustrated by this early picture of the Berci flock, including some of the founders:

Berci flock in early 1990s

Without the introduction of any additional genetic input for about two decades, this homogeneous look would persist as descendants of the original flock expanded in number and spread geographically across the U.S. and back into Canada.  There were no self-colored animals, either black (dark phase) or chocolate (light phase).  Shades of gray seldom if ever appeared.

All of that changed when Gaerllwyd Norris and Gaerllwyd Mustard rode into town in little plastic tubes.

Portable Mustard (top) & Norris (lower)

The tubes contained semen donated by Christine Williams in Wales.  The relevant parts of the donor rams’ job resumes are as follows:

Mustard, whose RBST registration number S10149 can be seen on the right-hand end of the upper set of straws, is a light phase ram of the “wild” or “mouflon” pattern (white or light tan belly and eye markings, light eyelid rims, light lips).  His pedigree tells us that he carries the gene for self-coloration.  Depending on who the mothers are, Mustard can sire brown, tan, chocolate, or black lambs — either in person or long-distance.

Norris, RBST number S10979 on his straws, is a brown-fleeced wild pattern ram.  But we know from his pedigree that he carries the gene for light phase and may also carry the gene for self-coloration, so he also can sire both light and dark phase lambs, and possibly self-colored ones as well.  The genetic potential of Mustard and Norris is no accident; they were selected by Christine and Kathie for the AI project with diversity foremost in mind.

March 28, 2008, our first day of AI lambing, began with the arrival of plain brown mouflon triplets (Norris x Galice), all three in under ten minutes.  We were speechless but elated.  The AI project had worked!  In fairly quick succession we welcomed a pair of twins, light phase as expected since both parents (Mustard x Gala) are light phase, and then the color fun started in earnest.  Josephine, inseminated by Norris, dropped a black ewe, Vieva, the likes of which we had never seen.  Although Vieva looked black when she came out (sopping wet lambs often look darker until their moms get them cleaned off), on close examination we saw that she was not quite the same jet black common in many mammals (Icelandic sheep, border collies, many other mammalian species).  Instead, from the start she was more of a uniform very dark charcoal color, with her belly gradually lightening and lighter hairs appearing around her back end.  But no way was Vieva the typical mouflon pattern.  Here she is at birth and as she grew:

Vieva, age 1 day, Norris daughter

Vieva, age 7 weeks

Vieva, age 2 years, with sunbleached fleece

Another one of our first crop of AI lambs — Curtis out of Norris x Louisiana — also displayed the new uniform charcoal color and pattern, but not so dramatically as Vieva. As he matured, Curtis developed more eye margin contrast, and an impish white spot around his mouth, not reverting entirely to the more traditional British coloration, but not fully self-colored black, either.  Look at the contrast between Curtis and his plain brown twin Melvin, and then the contrast between Emmett, whose coloring could not be more typical, and his pasture buddy Curtis:

Melvin & Curtis (r), age 12 days, Norris sons

Curtis, age 2

Emmett (Mustard son) & Curtis (Norris son), age 1 yr

Nice pictures, but what does all this mean and why does it matter?

The increased variety of colors and patterns in our British Soay is a visual treat and always intriguing to my resident geneticist.  Even more important is the message this additional phenotypic variability sends about the significance of the AI project.  The new colors and patterns are just the tip of the genetic iceberg.  They are the only part of the infusion of new genetics we can see, but Mustard and Norris have introduced a great many other new genes.  We probably will never know the full extent or identity of all this new genetic material, or precisely what roles each new gene plays in the health and vigor of our flock. What we do know is that the enhanced genetic diversity resulting from the addition of Mustard and Norris to the list of founders increases the extent to which the North American flock reflects the sheep of St. Kilda.  It also re-affirms the need to support efforts to preserve and conserve this genetic heritage through careful conservation breeding.

As you can imagine, we finished our 2008 lambing season in a state of high excitement.  Little did we appreciate what lay ahead.  The second round of AI lambs in 2009 brought more surprises and even more color variety.  I’ll brag on that batch of lambs in my next post.

For now …

Let’s start with a couple of examples to get you oriented.  The telltale signs to watch for first-off are the pale skin next to the eyes, almost translucent, and the equally pale lips.

This light phase ram, Hershey, also had extremely light fleece.  But note the fleece of the ram in the foreground of the picture.  He clearly is a dark phase animal, yet his dark fleece has bleached to almost as light as Hershey’s fleece.  Later in this pictorial tutorial I’ll show you how to use fleece to help decide whether an animal is light phase.  For now, let’s stick to the eyes and lips.

Although the next lamb shown has luxurious reddish fleece, much darker than Hershey’s fleece shown above, you can tell the lamb is light phase by her telltale pale lips and eye margins.

and a closeup shot of the same lamb’s face:

Red Deer, shown next, also was a light phase ram.  Look at his pale lips and eye margins.

Same ram, closeup to give you a better idea of what to look for around the eyelids and lips.

Time for compare and contrast.  The next picture shows a dark phase Soay ram with fairly light fleece (sun-bleached tips), but definitely not a light phase.  Notice how dark the skin is around his eyes, sort of like the horrible black eyeliner women wore in the 60s.   Dark, often nearly black, skin right next to the eyes is the most immediately noticeable difference between the relatively uncommon light phase Soay and the predominant dark phase Soay.

Many Soay sheep carry the recessive gene for light phase, but they are not themselves light phase animals.  They can produce light phase lambs when bred to a light phase animal.  Every lamb from this breeding has a 50% chance of being light phase because it has to get one gene for light phase from its light phase parent, and it has a 1-in-2 chance of getting its other parent’s light phase gene.  The carrier also can produce a light phase lamb when bred to another light phase carrier, but the chances of the lamb being light phase will be only 1-in-4.

The next two pictures show two of the most beautiful ewes to grace our pastures, Nell and Sandpiper.  They both carry — but do not express — the recessive gene for light phase.  For purposes of this post, the important fact is that neither Nell nor Sandpiper is a light phase ewe, and you can see that they are not light phase when you look at … what?  Their eye margins and their lips.  First, the two of them posing to show off their lovely light colored fleece.

And now the giveaway closeup.  Look at the dark “eyeliner” and lips:

The difference between light phase and dark phase also shows up dramatically in lambs.  The next picture shows twin lambs, one light phase (on the left) and the other dark phase (on the right).  As you can see, both of them have light fleece.  In fact, the dark phase lamb had lighter fleece at the time this picture was taken.

The more chocolate-y fleece of the light phase lamb is typical.  We have been fooled, at first glance, by lambs we assumed were dark phase because they had medium brown fleece, but their eyelids and lips gave them away as light phase, and their fleece lightened as they grew older.

The next two photos show the light phase lamb, and then the dark phase lamb, up close.  You should be able to see a distinct difference in their eyelids and lips.  Here’s the light phase lamb.

and here’s the dark phase lamb.

A third characteristic shared by all light phase Soay (besides eyelids and lips) is pale skin right under the tail.  Two years ago one of our first AI lambs, light phase Arzie, struck a lovely pose for the camera, showing her pale eyelids and lips,

and then without warning she turned around to display the pale skin under her tail — talk about lucky timing for the photographer!

Caveat: Although many dark phase Soay sheep have dark, nearly black, skin under their tails, an awfully lot of them have the same pale skin back there as light phase sheep. Truth to tell, I might have left out this “distinguishing” characteristic altogether if little Arzie had not flashed her bum for me without having to be picked up and put through the indignity of a posed photo of her back end.

Yet another hint in distinguishing light phase from dark phase is provided by the roots of the fleece.  In light phase sheep, the fleece will be light or medium brown all the way to the skin, even if the tips are noticeably lighter from sun bleaching.

In dark phase sheep, even if the fleece is bleached quite light, as in this “frosty” Soay, the roots will be really dark brown and appear black.  Here’s an example:

Okay, are you ready for the quiz?  First up is Fennel.  Look at her gorgeous fleece.  Light phase or dark phase?

Would you like a closeup to help you decide?

A:  Dark phase.

How about this sweet little lamb – light or dark phase?

A:  Light phase.

In closing, I have a confession to make.   Despite Steve’s heroic efforts to persuade me that the most important aspect of our breeding program is our strict rotational conservation breeding in which we do not choose matings by the handsomeness of the parents or by what color fleece they have, I remain a total sap when it comes to light phase Soay.  For me, there is nothing more endearing than the pale lips, winsome fawn-like eyes, and creamy light reddish fleece of the light phase lambs.  Hooray for recessive genes!

For now …

And so it was out of self-defense that I recently went on the web looking for places to read about the genetics of inheritance in order to understand why it is that Grace gave us a light-phase ram lamb and Celadon surprised me her first year with a black lamb.  I know, I can always ask Steve, and how lucky I am to have this resource right in my own home.   Don’t get me wrong.  It is great being able to ask the professor without waiting for office hours.  But after six decades of this life business, my powers of retention are shot, and I am too proud to ask Steve to explain what a chromosome is for the umpteenth time.   

Finding good sources of information was easier than I thought it would be.  I was not interested in a book so heavy it would serve better as a doorstop, nor one that consisted of nothing more than stick figures and cartoon balloons above dividing cells.  I have read Genetics for Dummies and its section on patterns of inheritance does not take you very far.  What I wanted was something I could work my way through in the mornings over a cup of coffee and without the distractions of chores or piano practicing.  There doubtless are dozens of similar sites, but three I found without much effort helped me and I hope they will help you, too.  They should give you enough background and knowledge of the jargon to make you more comfortable about what’s going on with color and horns and other characteristics of your Soay, without falling into the black hole of academic genetics that swallowed up Steve decades ago.

Morgan, a multimedia tutorial from Rutgers University, covers the basic principles of  genetics.   Each chapter has ten distinct parts you can work through at your own pace and then test yourself with their short quiz to see if you “get it.”  

Dr. Steven Carr, Department of Biology, Memorial University in Newfoundland, Canada, has put together a dandy one-page chart of Mendelian rules summarizing the definitions and basic rules of inheritance.  It is a little intimidating at first because cramming so much information onto one page makes it pretty dense to read, but if you work your way carefully through the chart and the definitions, you will end up smarter at the end of the page than when you started.  It is a good place to look back at for a refresher when someone starts yattering about “double heterozygotes” just when you are trying to finish cooking dinner. 

The American Mathematical Society has put together a detailed but not fatally technical summary of molecular biology and genetics.  It is a good “next step” after the first two sources.  You will need to read it when you are rested, as the typeface is maddeningly small and they wasted no time on the niceties of page layout, but it is rich in content and provides an overall context for the narrower issues of horn shape and fleece color we all face with our Soay sheep. 

It may be that simply living in the same house with a geneticist for over 36 years has skewed my notions of beginning genetics, so I would appreciate if you let me know whether you find these sources useful.  In any case, I promise there will not be a quiz next week, or any time soon.     

For now …