I. .Y/2c.Yu&t0/l Genetics in Friesian Horses Presented at the FHANA AGM February 2008

by Dr. Hein van Haeringen, DVM, PhD [email protected] Together with Dr. Wim van Haeringen, PhD [email protected]

From notes taken by Laurie Kasperek lr1troduction D,: Hein van Haeringen was originally destined to be a farmer • Hein van Haeringen but plans changed when he allended the University ofUtrecht and • Veterinarian (1969) graduated with a veterinarian degree in 1969. He went back/or • PhD (1974) further education and earned a PhD in 1974 in Bacteriology. He worked in various animal health and blood typingfacilitiesfora • Animal Health Service (1969 - 1977) time until founding the genetics laboratOJJ1 that bears his name: • Director Bloodtyping Unit (1977 -1986) the D,: Van Haeringen Laboratorium (VHL) in Wageningen, The • Dr. Van Haeringen Laboratorium (VHL) Netherlands. ( 1986 - 2003) The VHL employs over 30 scientists and researchers and a 11e1\' branch has recently been opened in Belgium. The lab services breed registries of many types of livestock, governments. and universities around the world. They hold the DNA data for the Hein KFPS and work closely with the studbook. In 2003, Hein turned the helm of the VHL over to his son, Wim . who continues the excellence of the lab. Hein has contributed a number ofarticles to THE FRIES/AN, beginning in 2003 with hi., .first contribution on neonatal isoe1ythrolysis (NI). He has conti11- ued to supply NI information to FHANA, as well as information about the possibilities of starting a genetic databasejor Nort h American Friesian horses. Hein still travels the world in genetic consultations and FHANA was ve,y pleased to have him as ow keynote speaker at the 2008 AGM. The following notes were take 11 dunng the presentation by the editor of THE FRIES/AN.

The ~iscussion will cover the differences between the extenial genetics and the internal genetics of a horse. External genetics is Today's Programme ~he phenotype_ of!he horse, what is seen on the outside, while the mterna~ genetics is the genotype. Blood typing will be discussed. in particular parent · . • ·11 • Genetics external (outside. phenotype) . ' age venficat1on and NI. DNA basics wi • Genetics internal (inside, genotype) be discussed lead· . . .' mg to an explanation of DNA in parentage • Blood typing venficat1on m genef ct · d • , Parentage verification ' ic isor ers, and in the single-gene recesSI' e NI • DNA aL~osom~l and how this plays a role in our horses' genetics. Finally. Background Parentage verification ad t1sctLl1ss1on on a genetic database will cover the collection of the I Genetic disorders a a , 1e actual bank· f Single Gene Recessive Autosomal that ultimately . I mg o the material and data. and the researc i • Data is tie product of a database. Collection Bank Research • Future

2(, Ex\ema\ Genetics (1)

• Start. of\he Studbook \879 Radboud \9was bom Sire Unknov«1

• OestripUon of the breed Selection tri\eria fannorShow? Riding Coaches Jumping or Oressage?

• Breeding Colour tBlack??) Height Movement Hair grov.\h

Externa\ Genetics (2) External Genetics (Phenotype) Fina\ goa\ 1' o A description choose the best one of the external genetics of according to the the start of the t db Friesians ooes back to goa\ of that k · 0 time·, s u oo m 1879 when a . . was set down descnpt1on of the breed No know\edge . Radboud l 9 was born to to use internet\ pheno~pe an unknown sire. The genetic of the Friesian is characteristics. used by the studbook to specify selection criteria for approved the stallions and for the rewarded at inspections. premiums The phenotype also detern1ines usage of the best a particular horse; will the horse be better at farm work or on the show circuit, as a riding horse or a coach horse as a jumping horse , or even or a dressage horse. The phenotype in breeding considerations. is also used The studbook calls l 900 there for black horses. In were other colors in the Friesian phenotype horse, but black is the desired. Breeders also consider growth, the horses' height hair and movement, all external genetic components. The goal is always to choose the best phenotype the stated according to goal of the time. It took awhile the before we understood inside of the horse , the genotype. This is fairly recent so the phenotype was the only characteristic that could be used. Equine blood oxygenates in 30 minutes. After in a test tube this time tl~e blood will have a clear upper layer composed of plasma, a white layer of white blood cells, and a la_yer of red bloo? cells the bottom. The white blood on cell layer 1s the source ol DNA testing. for

Internal Genetics (Genotype)

.fi f on Parentage ven ca 1 in animals came about first \nterna\ Genet\cs W in cattle after Id W Researchers were able · ·r ·d, · • l the_ second u ~r bloo~r.typing. to idenll y i t:nt1ca For horses, blood • Understanding twins thro typing began in genetics and tools to g d ~ parentage verification assess variation 1970 and was use and the studbooks. an or d b . ndividual breeders • Cattle It also b to be use y I for assistance in were leading eg ty . . . dealing with NL The geno is a tool to assessmg the va Blood t'jping since 1950 pe , nat1on Identical Twins in a population . Parentage • Horses Blood t'jping since 1970 Used for parentage & Studbooks NI - Individual breeders Blood Typing Horses (1) Blood Typing Horses

• First test In Holland 1973 ed in Holland in 1973. This was the Horses were firS t bloo~ Mark 232) was born. The first test in • Hearke 254 was born (Mark 232) 54 1~ • First test In Fnes1ans 1975 year that Hearke 2 (sirel . y as the year that Lammert 260 (sired · · 111· 1975 T11sW · • Lammert 260 was born (Bjinse 241) Fnesians was · There are DNA differences between by Bjinse 24 I) was born.I Warmbloods have a larger gene pool . iple Dute 1 • Differences in breeds bree d s. F 01 exan . · . . ns have lower numbers of genes in F . . Smee Fnes1a • Population studies than nesians. ftests must be extended. This variety th • Vanety differs per breed the population, e batterydo a number of factors. including how b b eds can depen o1 1 • Many stallions? etween ~e . ulation and the number and extent of 1 0 • Bottle necks ? many stallions are 111 t ,e P ~ bottlenecks in the breed's history.

til the early 1990's and it was a strong Blood typing was use d un ·b . and control was poss1 le, but the flip . id seful tool Preven tion at u · . d a shocking component - someone could Blood Typing Horses (2) side of this was that it 1,a see my breeding errors! • Developments till early 1990s • Strong and useful tool groups and breeding ls there a re Iat1ons · h"p1 between blood characteristics? NO! Prevention: Control is possible Shocking: Someone can see my errors Blood typing only lasted for two decades and then it was replaced with DNA. • Relationship with breeding characters : NO • Only two decades and then replaced by DNA Neonatal Isoerythrolysis (NI)

Much has been published in THE FRIESLAN already regarding NI so this will be an overview. NI has become an important and ho; issue for breeders who have experienced the problem. Once NI (1) experienced, it cannot be ignored. BE HONEST. Tell the owner of a mare of the NI risks because the buyer could lose a foal ; this i, • Hot issue for breeders who know the a priority of all breeders and owners. It may not be a first priori i trouble for the studbook, since it is a combination issue in the breedi r • BE HONEST but every breeder needs to understand and prepare for NI. • Not first priority for studbooks There are two active blood groups in Friesians: Aa and Qc. Le • Much information already in FHANA important are the blood factors Ca, Pa and Ua. The Qa that is fou • Some highlights in Thoroughbreds doesn't exist in Friesians. A foal is at risk of­ when a mare is lacking a factor and the stallion is positive for ,

The University of California at Davis has been doing the test t NI risk factors in the laboratory of Dr. Ann Bowling until hLr ~eath. Without_her leadership the lab stopped this activity and it NI (2) ~snow housed ma local private clinic. The majority of NI testnig 1s h_oused at the University of Kentucky, Lexington. so that 1s a to have NI testing done. It is not recommended W • Important factors in Friesians logical place spread information between 2 or 3 labs. but rather to conduct tests • Aa and Qc all 111 one location where possible. The-contact at Kentucky is Dr. • Less important Kathryn Graves. • Ca, Pa and Ua • When at risk: Mare lacking these factors + Stallion positive

28 N ~ (3) There are a ,\1'1111. ~I.IY '"'" then1 I . . nun1ber r . • Fairy tales I lat is still o fairy tales . foal is not . heard. eve associated with NJ One f • First foal not at risk I at risk Tl . n an1ong pra 1· . . o lave disco, . 11s is Very d fi . 'c ll1oners, is that a first 'erect Iii" e n1tely fals E ., Introduction of foals to the mare A nother w1·d I is. n1uch to th . ct· e. ven colleagues s after 3 da e y ac e1r ismay and ct · . ... O lder mares without a previous NI h . ys need to be , cepted fairy tal . isappo111tmen1. 1st0 Why separated for thr not develop NI ry do d e is that the mare and foal only foal o~i end tl'.ree days wo;iin ays. Again, this has proven fal se. It. y to reintroduce th g hard to separate the mare and Three times 'NO'. fi is tafe to reintroduce th e~n prematurely and have the foal die? na ~Y, the fairy tale tha e oal to the mare after FIVE days. And !'II history Will not d : an older mare without any previous indeed develop NI I eve op NI is also false! She can and may right in her past hi~t t can be that the c~nditions were never just N~(4) o1y lo develop this problem before. The origin of NI · st- Comments & Remarks: is i11 mostly unknown. Origin of the placenta damage Unknown There is con Fusi . . reco on regard mg the tiler results and what has been Titer When positive? 111111 nd · ~ ed. A titer before birth of 1:2 is not a positive but New developments a titer of 1·8 · · • ' · is positive and a muzzle is required. All positive and high titers. fi ~raaf-Roelfsema et al . Vet Rec 2007 Aug 11 ;161(6) 2 A new development in NI has been published by DeGraaf­ Prevention Roelfsema, et. al. They have found an antibody that is killing Testing all mares and stallions? every red cell and the reasons are not known as yet. There are Families at risk? 7 to IO documented cases of this. Choosing partners

NI is genetics but do not call it a Disorder! To prevent the birth ofNI foals test all stallions and mares. Some families can have a higher frequency of NI, so the prevention is to choose another partner. Remember to test all donors and replacement colostrum prior to using. NI is completely nature GeneUcs - remember that NI mares DO NOT EXIST. NI is genetics but (1) it is not a disorder!

• Some statements Genetics Genetics ,s not a fixed situation . . iot a fixed situation· changes G enet1cs 1s 1 ' occur at either. a fast r Changing fast or slow ·ate v1·1·uses for example, can change rapidly and or a s Iow · ' . · o d ~- In viruses sometimes going fast we' ve 'all heard ofis the bird flu. Tl11S has rap'.dly chan,,,e one ti d ·n l1umans. Genetic changes Ill mammals Bird flu now in human ow be oun I • • Not yet spreading from human to human to n These genetic changes are often seen m are much slower. . d t1·on such as the number of piglets • Genetics changes in mammals slower · and rep10 uc , product101~ ' I . I I s slowly increased over time. Litter size in pigs born in a litter w 11c 1 rn Production and Reproduction be detected relatively easily. An .n ale gene effects can ft'ect is the chestnut factor that SI o · ale aene e · I example of the Sil~::, l~e KFPS . On the other hand, _multtp _e VHL isolated tort d"fficult to detect, taking mote t I1e d I y are more 1 . T d aenes interact an t 1e It" le genes interacting are tert1 ity an Genetics (2) =: Examples of mu tp time, height. ONA blocks _ a portion • Single gene effects . of the d. O,·cur in one d so o11 Recent stu ies • One gene, direct effect · 5 ca n .., fl · d an · M utat1on . sing. lost. ippe ' . d that the chromosomes • Chestnut 11e 111 15 • · I ve foun ' · can becor 1· ked infertility ia . tl1er chromosome is • Detection relatively easy . ex 111 . d or ano exploring s . s are sw1tc 11e ' d· piece ' , ti ere • Complex situations are change . lly wouldn t be 1 . ' I r norma • Multiple genes interacting present t ia • Examples :!.') • Fertility • Height • More- 1'i9ult to de e.ct • e · b .··step I.

Chromosome - DNA

• Chromosome based on long chains of DNA

locks (A, T, G and C) CHROMOSO~ ,J..

~ ' •,, • DNA sequence ATCGGTCGT AATGG

5\ :i.~ DNA Karyotypes DNA Background

The slides show that the structure of _a ~hromosome is long ' '' Human 23 pair chains of DNA . DNA is built of 4 building blocks called A, / I 2 3 T, G, and c. These four blocks, when arranged in sequences. Cat 19 pair form amino acids and proteins that comprise DNA. Specific )·t' ·H -,., H ·)t Horse 32 pair numbers of paired chromosomes form the karyotype of every II \ Ja . animal (left). 6 7 8 9 10 Cattle 30 pair Tllf}( X ·tt DNA is a better tool than blood typing and it has become very lJ 14 Goat 30 pair l ~ 16 17 important for breeding. DNA in parentage verification was first ·tt· ·H· .,. Dog 39 pair used in Holland in 1994, the year that Grad us 356 (Reitse 272) x was born . DNA uses more markers and better conclusions can be made than with blood typing. All countries use the same set or markers . A particular DNA marker could be used to com e up with a better horse (but the first question is "What is a bet­ DNA Background (1) ter horse?").

• Important for animal breeding • Parentage verification Mutations can be detected through DNA investigations. Ii one block of the seque,1 · · • . First test in Holland 1994 GRADUS 356 was born . ce 1s missing than the correct amin t (Re1tse 272) acids and proteins ar · · N an ellect.. ., though ande missing.t ot every mutation will shm Better conclusions than blood typing: more errors detected M . , no every abnormality is unpl easan t Number of markers to be used depends on variety of utat,ons are used all ti • . markers withrn a breed breede. d'd , . le time in selection but maybe th, , , n t even know ti . ~ • Population genetics pos,·t· we . 1ls •act! Mutations can indeed b, Differences between breeds • Marker Assisted Selection • Detection of mutations Not all mutations geneticall b . . . tations are non,, II Y ehave identically. Dommant mu- a Y Iethal res it· · . . . , u 1ng 111 abortion or still b111h . DNA Background (2)

• DNA is the key to produce amino acids and DNA Background (3) proteins Do all mutatio . • If DNA is rearranged = MUTATION • Dominant ns genetically behave identica l? • Consequence: not the correct/ usual amino acids & proteins Many are lethal • Abortion or Stillbirth • Direct result: abnormalities • No spreading In popufatlon • Do not panic! • S ex related • Not each mutation shows an effect More chance for I . • Cofourbll•d" Inmen Illa es == Single copy X/Y chromosome • Not each abnormality is unpleasant X chromosome • Part of selection is based on mutations • Only remales - considered as positive • Single Qene - - definitely X Chromosom e Nor on X - autosoma1 recessive . or :Y. chromosome I!, \.l'l!!L 'I\\ ••r- ~Sex related rnu tati . . ni ales since . ons tend to have a higher chance of occumng tn DNA Background (4) a s1n 2le · alI that is ne d d ~ copy of either the X or the Y chromosome as

A sin ole O e e · An example of this is color blindness in humans. • Single ~ <'ene autoso I gene autosomal recessive and niost ct · ma mutation is not on the sex chromosomes isorde rs a d . - eeded. • Most frequent cause of genetic disorders both a . re ue to this torm. Two parents are n re earners d h anf • Both parents earner of a the same mutation S.\'nipt oms. · an t e parents iend to not sho,, oum • Parents mostly without symptoms • Mendelian Inheritance Offspring: Not all abno r . , G . rrn a !lies are 2enetic! The two slides belo,, - ~ oo 25 % show disorder (affected) enet1c Facto ~ . rua.J 50% are carrier of the mutation d1i1er.A' ences bet\rs. and Gene tic Disorders ( I ) - sho. . w the us • 25% tree of the mutation L \ een these two types of abnonnabnes.

Genetic Disorders (1) Non Genetic Factors • Spread over farms • NOT ALL ABNORMALITIES ARE GENETIC: • Slarts With a few cases • Toxicology = Poisoning • AU kind of abnonnalilies depending on lht age of Iha embryo • Exactly similar defects Mostly one rann or region Many newboms affected • Sometimes lethal (Abortion or Stillbirth) • Infections • Not always visible at birth Virus Mostly a specific effect Depending on lhe age of embryo His1ory of mares with a disease Rhinopneurnonla ViJUs • Reason unknown Mos1 frustrating Reseerth may decrease the numbers wilhln thiS group

The spreading of a sim!le !!.ene disorder \\i ll be se-en in less than 50% of those who could h~w the mutation. This depends partly on what number in the population may ha\·e aboned or been still Genetic Disorders (2) born due to the mutation. At the outset of the mutation. the gender of the first carrier will play a role. Obviously, if this first carrier is • Spreading of a single gene a gelding his entire life. it is the end oft.he story. If the first carrier • Less than 50% ever to be seen is a mare, it will be spread but in a slow manner. Howewr. if the • Depends (Abortion I stillbirth) first carrier is a stallion. the mutation can be spread very fast. • Gender of the first mutation carrier Single gene disorders only occur when two carriers produce a foal • Gelding end of the story and the chance of the fo~l bein!!. affected is 25%. The chance of • Mare slow and not very many the foal being a carrier is 50%.- It takes 6 10 7 generations after • Stallion can go fast! the onset of a mutation for it to be seen!

Which genetic disorders are in Friesians? DO NOT TRUST THE LIST BELOW. The only one for sure is dwarfism.

Genetic Di sorders (3) Genetic Disorders (4)

• Detection of a single gene • Which ones in Fnesian? • Dwarf ism • On~y 1f TWG carriers are producing a foal Back W el al 2008 Equ111e Vet J ,5% affected foals • Waterhead Six or se ven ge nerat1ons after s•,art of th e mutation • White hairs Definition 1951 President Mr Anema Wlule spollrng rt there are any black ha~ ~ the v.Meones Star no black haw; between the \\tl~e hair; • Aorta rupture lnhentance? • Mega esophagus lnhentance? • FertMy lnhentance? • OCD lnhentance"

31 ~ n ·with a larger sample si~ , ·11 t be prove . . e 1Ore Waterhead has st1 ° . ,I ,ene recessive autosomat. A • d s a sing e g • • • . Ort a Two Friesian d warves 1t can be state a ' . . yet known 1t It 1s genetic. I I . t but it is no 1 b iave rupture does ex1 s • mega-esophagus ut the study . d the paper on \Va s read and stu d1e d ere the sample would tend to\, ries Ian w I1 'ard located c Iose to F . a random sample. In addit" · I F -· s1ans. no 1 10n predominant Y I ie ' · c renced cases do not appear b •. · all the reie 10 e the symptoms 111 ' . ·r presentation. More studi es would 11 completely identical 111 ,ei conclusion can be drawn. Ferri· t d before any I ny need to be con d uc e . • vestigate and resolve. issues will take a long time to in . ew mutation, it is a natural coat colo The chestnut factor is n~t an in practice in the early histo r. Had parentage verificatwn been . t ry of would not ex1s now. the studbook, th an chestnu t

Single Gene Dominant . . . copy of the gene 1s necessary to have an In this sceneno on 1Y one . • . e coming from either parent. A recently affected a111ma 1, t1 1e gen . . . . d k t of the University of Mmnesota describes such pu bl 1s 11e wor ou . . _ PSSM (Polysaccharide Storage Myopathy). This 1s also a one h F . . . k nown M as on d ay Mornl·11g Sickness and t e nes1an 1s known to have PSSM. Ninety percent of PSSM cases are due to a mutation and Minnesota has a patented DNA test available. There has been a muscle biopsy test previously. Afflicted horses have low appetites, reluctance to move in work, inability to often backup, poor muscle development, etc. Most PSSM cases respond to a change in diet that is away from high sugars since this is a sugar storage problem . There are two types of PSSM, as the new literature points out: the less severe type where it is inherited from one parent and the more severe type where it is inherited from both parents. With the DNA test, all owners can test horses and make the proper diet and management changes before this disorder becomes a problem. In addition, the DNA tests will allow researchers to determine th e • Most probably another story extent of PSSM in the Friesian population. • Technically a mutation, but not a disorder • Not a mutation in Friesians, but a natural coat colour It is important to be HONEST and to be CAREFUL. Once a variant from other breeds (decades ago) label is placed on a horse it is there forever. It needs to be true. • Parentage verification 1 • First d iagnostic test in FrIesians 1999 Remember: not every abnormality is genetic! In order to be sure Wobke 403 (Fetse 349) the proper data is collected, the breeder must take a photograph W1kke 404 ( RItse 322) ~nd repo_rt only the facts of the case. Do provide all necessar) • Data Bank of laboratories such as VHL very 111format1on and an official necropsy report to the studbook. In useful return, the st~dbooks should make the process a positive one fo r • Many old stallions can be tested the breeders 111 recognition of their time and trouble.

Data Coliection ( 1)

• Information is needed Be honest • How? Who? When? What to do? Once a label is always a suspect • Breeder first identification • Studbook coordination Be careful • DeScription prior to start of data collection Not every abnormality is genetically Data C Data Collection (2) , 0 1kc · o lhc I . hon ., , a nct s Cit is a s •. iu lh e D• • Breeder R."11 enc1 to ll1 " , l1 (k ,vi1l1 tl•llah.ank \1'1111 'I\' '-- 1e1 b 1 , · • FACTS '-- s1 , •1111-, and only FACTS A 11 er -13 - , li e1 boot.; c itcnis that . , Fairy tales are not i"nportant 1 1 1 1 • Sire? Dam? Parentage verification!!! SUSPEc,, ~L~~tR :' Ci\; ~\~it bcc01~~~c1~:;~~ s1~~ uld record • Abortion what age? St ict.; to r~ . NOTTO o " Databank • stillbirth weight lldboot.;s . cpon111g th e r MAKE ASTALLION • Partus normal? 111 anne. · 111 turn _ _ acts. k '· l'he . I egistcr • First foal of a mare? eepin u. y a lso nee I th e fact <::, It safe LI . C to be ci . < s reported in • Gender? llttl rese . icu111spcct ab a confiden ti al • Post Mortem diagnosis Studbooks a1ch has produced out the data coll ected • Inform the Studbook data a nct bre d results. . Be careful to make a stallion a suspect Co ll e · e e ti . ct,o n T rs ct o not I Hngs such . he studb _,ave a confli ct . unique . ~s the pedio. ook is in a uniq of ,_merest in this hi story pos1t1on to kno~:~es a_nd offsprino w~1~I p~s1t1on to know . eta, Is of health""fi . ·'1 : reeders are in a , e, ti ity · a n d veterinary Data Collection (3)

• Studbooks Databank (1) • Register the facts • Data Collection

• SILENCE please! Once a label. .. .. • Conflict of Interest Breeder versus Studbook ? NO • studbook knows much • Keep it Confidential in a small group until at Pedigree least two proven cases Premiums Registered offspring • Costs? • Breeders know more Health Effect of treatments Invite the breeders to send information Character Fertility Vitality

Databank (2) Databank (3) • T o be registered • Date of birth • Which animals to include • Fir st foal of the mare? • All abnormalities • Abortion? When? • Stillbirth : When? Weight? Abnormalities if any? • All stallions • Gender • Reg number+ 3 generations pedigree • Mares? All? • All dis eases Who 1s the vet? • Ferti lity • Character • Reason of Death • Sold to ..

Do NOT trust your memory! Make records per animal!

Blood is preferred for the databank and onl y 10 ml is required. 1r the a nima l is deceased, the tips of the ears contain cartilage that Databank (4) has a lot of immature cells, making them a good source or DNA. Take only the end 3 c m for freezing. An important question to be • Storage decided prior to setting up a databank is w hether a ll samples w ill • BLOOD is preferred be stored at one locatio n or w hether samples will be divided and , 10 ml EDTA stored in two o r m ore locations. Multiple storage locations keep the samples safe in the eve~t ofa p_ower fa ilure o r natural disaster • Abnormal or dead : Ear tips 111 • Frozen in one of the storage locations. It 1s a nsk to store a ll samples • One place? or split samples? one location. • Needs a perfect registration of samples • ·tant question to answer is w ho pays for what • Howtong? Another. 1111po1f h osts' of storage I1?. • Costs , tests, and researc portions o t e c I. ,C/Ac, ½ i t:Jl{I// -- - , . ts 11 utli11ir11.! th~· 11w111:rsl 11 ~ . - 1 i\ pplirntwns . 1 Jncunii.: . . 1P 11t The d:i t11 h;111I-. n.: q1ri n.:s leg •~ , 1udlwok/ rcg1 stry in on.h:r lor rcs1:,11\:h Databank (5) th e d:11:i . Thi, sho1rld he th ~ .ts should spell ou t the co1l\tr:11 n1, o1 . . ·ted. l)11cunii.:II • · I . rii•hl to mak e dc c·1\ iun~·>7 . Ill Ill llllll 111 i; I h·]S I Ii.: 0 . ' 1lt: • Ownership rh~· us,· i11' th e d:illl - w _i c~ , •. . is vcr)' in1portan1 lo k ga ll } ddin. . . , r us . I . . c • Who 1s the owner of the stored material pre sich.:111 '! /\ cn1111111!lei.: . n kn ow what is 1appen111 g at th 1: 1r • Breeders should not bel bce:1u se everyo ne wa nt s .L . • needed before re search c. 111 hcgin·• c•1si.: 5 ari.: I I ·, ·1·1 · · • Legally approved documents lll'il!hborsl I low n1an y ' - • Wh o owns 11 c rcsu ts. i1 ~ ~houlu Th: 11u111bcr is IO to 12 casi.: s. I . rnc111bcrs shou Id have accc \'> t . . butt ie o 5t be th e studbook/rc gi ' Y th e n~s ull s of research.

Applications (1) pedigrees ( 1)

• Examination & Interpretation essive? • Pedigree information in case of abnormalities • Autosomal Rec • Which test? And where? • Everybody wants to know about his neighbour's trouble • Who decides? President? • How many cases you need? • When? • Costs? ts carrier! • Who is the owner of the results? • If true, both paren

Pedigrees . . Pedigrees (2) If a disorder is autosomal recessive then both parents are mdeed carriers. Be careful though - don't stop analyzing the pedigree if • Expanded pedigree analysis reveals you have a common ancestor in the fourth generation. Sometimes. true mode of inheritance or more likely, often times, you need to go back to 6 or 7 oenerations to find the real source of the disorder. Such a st artino b ~ point of a new mutation is called a FOUNDER. In 7 genera ti ons • • • • • • ■ • • • • • • • • • there are 256 parents to look at, so it can be hard to determine which is the real founder.

Th e good news is that some DNA tests will be available in 5 more years or less, such as dwarfism. The horse genome may not h: • Identical ancestors? completed due to the expenses involved, but enough infonnatici has been found to work on these tests.

Pedigrees (3) Pedigrees (4)

• Yes, see arrow • But: ■ Also previous generations may have other shared ancestors, ■ • • • • • • • • • • • ■ • ■ • • Has parentage been verified? • Every pedigree in Friesians goes back to the bottleneck, • Be careful When sticking a label to suspected horses! • But...

34 pedigrees (5) ~ship or Applications (2) . . mare x 3 stallions ~search • Real life. 1 • Research and developments tints or • earners or some genellc disease can be recogntzed • Tests WIii be avallabte one or two years? s? The • Important lo know how to handle earners (policy) define • Killing? • Out or breeding? t their • Use the Information to choose the partners begin? • NO carriers x Carriers • Carriers x Non Carriers ;hould Can ti,·, c ;1Tt1~•rs :ess to • Next generations: avoid new stallions being a carrier • Hunting & selection based on one gene Is a risk! • Maybe other posiltve genes are closely linked lo the undesired gene 1

Future (1) Future (2)

Dreaming about the long term future • Possible and Probable Sexi ng of semen • Gaulder (2008): Everything will be possible Selection of stallions but Now 200 starting and 5 OK? Not all is probable • V1t al 1ty • Theoretically there will the possibility of a 1 00% = Co nd1t1on perfect horse = Health but I think this is not probable that this will ever be the reality :leed ~e if nes, At this time the policy of the KFPS is NOT to eliminate or destroy >r 7 Future (3) known carriers. This could be one management policy, but the ting problem with "hunting" for one gene to eliminate is that, in doing ons • Genetics is still ·on the move' so, one may also eliminate desirable genes that are next to this one, tine near it, or associated with it. • New Mutations will occur We could lose important traits we want to keep along with the disorders. Additional ways to control these genes are in Applications (2). We will see more disorders; genetics ore • Breeders are also 'on the move' is not stagnant and neither are breeders. Breeders will always be be • Ideas about the breeding policy will change striving for the perfect horse, but that is not reality. ion • The ideal horse will always be a dream Geneticists have a role to work with the breeders and the studbooks to assist them to be happy with their Friesians throug h the breeding of healthy horses. ~('

Concluding Remarks Only as long as they understand • Breeders are important breeders and will assist them to be • Studbooks are important • Genetics is important Happy with their FRIESIANS • What is the role of th . . e genet1c1st? rJ