A genetics question - tan points on English Springer Spaniels. Discussions

Could someone give me an idea about how tan is carried through dogs and specifically in the English Springer (although I'm guessing it's the same for all breeds? :? ).

Have found a Sire for Isla, he's perfect but some of the litters he's sired have tan points. And I'm not a fan of Tan in the ESS!

He is Liver and White as are both his parents and none of them show tan.

Isla is Black and White and none of her "family" show tan either.

Hope that helps and thanx guys!

What do you mean by 'tan' in the ESS ?

Are you talking about a third colour in addition to liver & white / black & white (tri-colour) or are you talking about a tan 'tinge' often found found in the undercoat of the liver which sometimes grows through.

It's quite simple inheritance..... tanpoint is recessive to no tan points. So a non tanpointed dog can carry tanpoint, but not vice versa. It does get a little confusing because it's not the A locus that we're dealing with in Springers, as all are probably homozygous for tanpoint anyway, but another gene that allows tanpoint to show.

If this dog has already produced tan pointed pups, then he definitely carries it. Isla may be a carrier even though it isn't in her immediate family. It can be carried for many generations without showing. If she does carry, each pup born will have 25% chance of being tanpoint.

The gene in question here (the K locus) has now been discovered and a commercial DNA test developed, so if you really needed to know, you could find out if Isla does carry. If she doesn't, she won't produce tanpoint no matter what she's mated to.

http://homepage.usask.ca/~schmutz/brindle.html

I mean "tri colour", although this term isn't used in the ESS in the UK (but is used in the USA). The breed standard says:

"Liver and white, black and white, or either of these colours with tan markings."

Here's a pic to illustrate:

I thought Tri was used over here, Ann Corbett had one on the seminar at United Spaniel.

Ooh thanks for that, I knew you'd be lurking somewhere waiting to answer my genes question! ;-)

I can go back through Isla's pedigree for 3 generations on one one side with no tan and 5 generations on the other side with no tan. Does this lessen her probability for carrying tan, or does it not work like that.

Also you say that as the "sire" has produced tan pups he will carry it, but that if Isla didn't carry tan she wouldn't produce tan even if he carried it. Is it possible that he doesn't carry tan, just that the bitches he's been mated to do?

Ooh but are you saying that a tan dog can't produce tan pups, in which case the last paragraph becomes obsolete?

I'm confused!

I thought you were talking about a 'third' colour but wasn't sure. I've never really come accross this although I've only ever had liver & white Spaniels.

It may well be used, but it's not correct terminology if you get me?

TBH Phil I've only ever seen it in the Show type, never the Working type. God knows where it's come from, but it does make me chuckle. The BWs are disliked as there are rumours that Collies were introduced to increase trainability in the Breed (a looooong time ago). But surely if that's the case, that's where the tan has come from? So if it's in the Livers then surely both colours should be equally undesirable? :?

Pod will probably prove me wrong though!

Yes it does. Also, if her litter mates have been bred from and not produced tanpoint, and her parents from other litters.

No, both parents have to carry for it to appear in the pups, so he is defintely a carrier. If only one parent is a carrier, then they won't produce any tanpoints. Even if one parent is actually tanpoint, they still won't produce it if the other doesn't carry.

Nope, I'm not with you.... can't make out what you mean sorry :smt001

A fascinating topic. My springers have all been fairly 'short' L&W - Mainly Liver.(Badgercourt with some rytex)

An old thread has just been resurected funnily enough re - blood lines.

Thanks again for that, I'm starting to understand it a bit more now!

Basically I think I've taken you first paragraph on your first post wrong. When you said:

I took that to mean that only non tan pointed dogs can produce tan, but those that do show tan can't. But what you really meant was only those mated to a tan carrying dog can produce tan, whether it's showing or not?

In the same way that liver is only present if black isn't etc?

Also can I ask how the percentage works? Eg why the pups would only have a 25% chance of showing tan?

Fank yoo Pod!!!!

Ah yes sorry, I didn't explain very well. You've got it now

Ok, this bit isn't so easy to explain as I can't construct a table on here, so I'll have to find a website to explain.... hang on a mo

It really is facsinating as I've just realised that you get BW in the working type, but no tan! So perhaps the whole Collie thing is a load of rubbish?

Isla's kennel's brood bitch had some of the original founders of the Badgercourt kennel in there, so it's a small world!

Maccsicar Mint and Robson of Gwibernant are the two main ones, although we're talking 1970's!

Ah glad I'm getting there!

Thanks again!

http://www.physics.uwo.ca/science_olympics/events/grades_11_to_12/if_the_key_fits.html


On this page, scroll down to the punnett square (don't read the text on that page!). They're using the letter P, so we can apply this to the tanpoint colour and use capital P for non tanpoint, and p for tanpoint.

The sire's gene is on the top and the dam's on the left. They're both Pp - tanpoint carriers. You can see in the four boxes how they match up.

1 square = 25% PP - non tanpoints and non carriers

2 squares = 50% Pp - carriers

1 square = 25% pp - tanpoints


The way they match up during fertilisation is purely random, so obviously you can't expect to get that exact ratio every time. It's just easier to explian it by saying each pup born has a certain % chance.

Ah ok I get it. So basically 25% chance of showing tan and 75% chance of carrying tan including those that show tan. This recessive thing is very clever isn't it? You can imagine how early dog breeders were completely confused by the whole thing!

Very interesting stuff, thanks for all the info Pod. Very, very helpful!

Yes, great stuff Rips.... glad to help

It can be carried for many generations hence why the odd tan pointed poodle crops up here in UK lines as well! To be honest I think that all poodles are tan points it's just whether they carry the other gene that allows the pattern to be expressed.
BTW I love tan pointed springers :smt002
Becky

Hi, regarding the liver, white and tan English Springer Spaniels, it is more common in show type soringers but it is definitely in working lines also, We breed Working type English Springer Spaniels and know others,who have this gene as well as ourselves who have bred Liver, White and Tan English Springer Spaniels.

Very exciting and interesting