THE INHEI%ITANCE OF ~ED, ROAN AND I~q-IITE COAT COLOUP~ IN

]3Y I. CHESTER JONES, Del~ar~ment of Zoology, University of IAver2ool

(With Plates 6 and 7)

I. INTRODUCTION In , in the vast majority of cases, both red and white animals breed true for co]our and crosses between them give roans. The simplest explanation is that red and white are allelomorphs, the heterozygote giving roan (Wilson, 1908; Smith, 1925; Roberts, 1937). Some workers, recognizing the fundamental redness of Shorthorns, have suggested theories to meet this. Walther (1913) argued that the oolour must. be 'a fixed red', the white 'moving over a large area'. He postulated one ]?air of allelomorphs, therefore, white and the absence of white. Crew (1925) suggested that 'all Shorthorns may be reds...' and looked upon white as due to a modifying factor. Wright (i917), considering, the production of some animals with red pigment in the F 2 generation of white Shorthorn by Galloway crosses, postulated two pairs of altelomorphs--E, a factor for black allelomorpkic with e, a factor for red, and W, white, atlelomorphic with w, the absence of white, the heterozygote Ww g/~,-ing roan. Ibsen (1933), also concerned with ~he Shorthorn by Galloway crosses, posttflates two pairs of aUelomorphs--B, black, allelomorphic with b, absence of black and N, white, ailelo- morphic with n, absence of white..He further postulates hypostatic red (R) homozygous in abl cattle. There are certain exceptions to the general plan of inheritance which appear in all da~a whether taken from the herd books or collected directly in the field. Roans are occasion- ally recorded from red x red crosses and from white >: white, and both reds and whites occasionally appear from red x white and whites from red x roan. Such anomalous results have been explained in varioths ways. Those workers who have postulated theories to account for the genm'al plan of inherit a.nce, as mentioned above, have sometimes dismissed the except.ion,s as due [,o errors in recording or in identification (Wilson, ].908; WaIther, 1913; Smith, 1925); in other cases they have offered subsidiary hypotheses to account for them. Walther (1.913) and Smith 0925) suggest that roa.ning may be lost wi~h age and so lead to wrong ideritificat.ion. Wal~her (1913) suggests thai; the factors themselves may change quantitatively. Ibsen (1933) postulates a roan modifier, rm, which is recessive and which changes roan to red in t/he homozygo~.,s condition. Other workers, a.eeepting a~ least some exceptions as valid, have attempted to frame theories to embrace the complete data (Laughlia, 1911; Lloyd Joues & Evvard, 1916; Duck, ].923; Evvard, Shearer, Lindstrom & Stair.h, 1930). All such theories are tin- satisfactory in one way or another. Az pointed o~lt by other workers, some break down statistically, some demand genotypes which do nut exist (Wright, 1917; Crew, 1925; Smith, ].925; Gowen, 1927; Ibsen, 1933). Such theories need no~ be discussed here because the new facts, given below, show beyond all reasonable de,ubt that records which cq)l)ea,r 156 Inheritance of coat colour in cattle to be exceptional a.re in fiwt exceptional, b1~t that they have a very simple explanation which brings ~hem into the general scheme of inheritance.

II. N~w DATA Ia the 1)resent investigation the Duke of Westminster's Eaton Herd of Pedigree Dairy Shorthorn cattle has been studied: both in the fiek'[ and from the herd books as well as from private records and photographs. The ancestry of the existing herd w is taken back five generations. Two generations, and often a thirc[, are still in the herd and available for examination; fud&ermore, the majority of ~he recorded matings used herein are within the memory of the bailiff, Mr Pakenham HamiIton. Ever), combination of colours has been made in the matings and alI colour types have been produced, but breeders have a predilection in favour of some colours, and the numbers in these cases are over~veighted in the ~:ecorded results. Hence ~he ratios of the colours obtained iu the records have no significance. Reds and red-and-whites are here recorded as such but, for purpose of analysis, the red-and-whites are treated as reds, whi~e spotting being inherited as a separate character (Smith, 1925). Similarly, the roan-and-whites are treated as roans--to avoid confusion they are also recorded as roans~ for a small amount of white spotting on a light roan is not easy to identify with cergainty. A summary of the da~a obtained in the presen~ study is given in Table 1. The sex is not recorded, as reciprocal crosses give exactly similar results. Table 1 Roan includes roan-and-whlte. Results

Red and Type of cross Red white Roan White TerMs Red x red 16 12 2~ -- 30 Red x red-and-white 16 13 45 -- 33 Red-and-white x red- and-white 2 12 25 -- 16

White • red I$ -- 27 -- 28

White x red-and-white -- --- 16 -- 16 White • white Roan x red 66 31 126 15 224 Roan x red-and-white 27 52 98 I$ 178 ]~aIl X roall 28 45 177 47 297

Roan • white -- -- 21 12 33 Tonsils 156 165 473 62 856 ++ Unexpected on any monohybrid theory of roan. Counting red-and-whites as reds and roan-and-whites as roans, the crosses examined yield the results shown in Table 2. Table 2 Resldts A Type of cross 'Red Roan White Tot~s Red x red 71 85 -- 79 White x red lJ; 43 -- 44 White x white -- -- 1 1 Roan x red 176 224 2~: 402 Roan xroan 73 177 47 297 Roan • white -- 21 12 33 Totals 321 473 62 856 :~ Unexpected on any monohybrid theory of roam w Tn 193.9. I. CHESTER Jo_~Es 157

IlI. DlscrJssm~ OF rxE GENE]~AL 8CttEI~{E OF INtIERrrA~NCE These data. correspond closely with those collected by ethel workers. Apart from the exceptions to be discussed below, they could be explained by considering red and white as a.llelomorphs. This theory, however, deman&~ the absence of red in white animals and, as many workers have realized, is unsatisfa.ctory in the light of white Shorthorn by Galloway crosses. Further, it is entirely out of halanony with the observed facts of pigment distribution. White Shorthorns are never without visible i'ed in the coat--about the ears and in the eyelashes--and microscopically the white hairs themselves all show some small amount of red pigment (unpublished data). It seems eddent, therefore, that all Shorthorns are red, as Crew (1925) suggested, and the only remaining question is whether their red is the allele of the black of black breeds, as postulated by Wright (1917), or whether red is hypostatic as postulated by Ibsen (1933). From Bogart & Ibsea's observa- tions (1937) and from o~r own (unpublished), it is ceAain that homozygous black hair contains red pigment so that black and. red cannot be allelomorphs. It seems most probable, therefore, that both black breeds and Shorthorns contain hypostatic red. The scheme of inheritance therefore which most satisfactorily meets our own observed fact~ is that put forward by Ibsen in 1933: R =red--always homozygous. N =white--causes hair of any colonr to become devoid of pigment, incompletely dominant. n = not white--leaves the hair pigmented. Thus, red = RRma, roan =RRNn, white =RRNN. For the black of Gatloways Ibsen postulates a factol' B, allelomorphic with b, which gives absence of black. Thus the feminine for the main colour types involved in the white Shorthorn x Galloway croas ~dll be: Black BBnn or Bbma "] Red bbma I White hbNN ~. with red (R) homozygous in all cases. Red roan bbNn [ Blue roan BBNn or BbNn J This scheme takes no aceount of ~he variaLions in shade of red in Shorthorns--variations which are of even wider range in cattle as a whole. The constitution of red is by no means fully understood, and the absence of a known allele presents difficulty. But that red is present seems beyond doubt and the postulate of homozygous hypos~atie red (R) meets the case, though only in the nature of a first ap]?roxhn-'~tion. Ibsen's 1933 theory of colour inLeritance was modified by Bogart & Ibsen in 1937 because they believed that they had demoJis~i'a.ted black pigment in red and white hair. Microscopic studies similar to theirs ha.re been ma~te in the course of the. present investiga- tion and have entirely failed to reveal any black pigu'ient in either red or white hair of Shorthorns. Furthermore, results exactly similar to theirs, but, in our case certainly false, can be obtained readily by certah~ metho& of examination and this, we believe, is the explanation of their findings. We hope to publish the results of our own studies of piginentation shortly, when the question of both black and red pigment will be more fully discussed. 158 Inheritanc~ of coat colour in dairy shorthorn cattle

IV. E:KOEI~TIONS" .~NALYSIS AND DISCUSSION On the theory here postulated there are eleven uaexpected result~ show~ in Table I"

Red • red gave roan in 2 c~sea l~ed x red-and-white gave roan in 4 c~es Red-and-white x red-and-white gave roan in 2 cases Red x white gave red in 1 case Red x roan gave white in 1 ease l~ed-and-white x roart gave white in 1 case In view of the possibility of herd-book errors (o[ the clerical type), the eleven unexpected animals, recorded above, have been exambaed as far as possible to check the colonr. In two cases (1 and 2, below) we have seen the animals themselves, Eaton Waterloo Swell and Woodhull Grey, and there is no doubt that they are correctly ~egistered. In six other cases we have excellent photographs, and Jn four of these (3, 5, 7 and 9, below) the description is certainly correct- they are described as roans and the photographs show them unmistakably ~s such. In the other two cases (4 and 8, below) it is almost certain that the registered description is correct, btte as one is white and the ocher red it is not possible to be as cereain, from a photograph, as in the case of roans. In only three cases have we been unable to check the registered descriptions (6, t0 and 11, below). The same possibility of clerical errors in the herd-books arises also in regard to the sire and dam of an unexpected animal. Therefore these, too, have been checked as far as possible for colonr. In some instances the animals themselves have been examined, in others gooct photo- graphs have been available, and in all these oases the animals appear to be as registered. In a few instances it has not been possible to check the colour, but there are several cases where sire, dam and offspring have all been sufficiently checked to make it practically certain that in these cases at least there has been no herd-book error of the clerical type (1, 3, 5 and 7, below). There is always, however, the possibility of mistaken identity. The most striking feature in a Shorthorn herd is ~he extreme variation in the degree of roaning (P1. 6, figs. 1-12). Some roans have so little whi~ in the coat that it is easy to mistake them for reds, others are so white that only close examination shows them to be roans, and this must inevitably result in some animals being wrongly described and so misregistered. Wilson (1908), Laughlh~ (1911), Walther (1913), Wentworth (1913) and Smith (i925) have all no~ed such cases of wrong description. Ft~rthermore, early in the coarse of the present investigation, working with the animals in the field, it seemed tmlikely that the visible limits of variation are in fact its full limits. If a roan can be so nearly red as to be mistaken for red it seemed probable that they are sometimes just that slight degree more red which would make them truly phenotypicatly red and, similarly, that occasionally they may be phenotypically white. In that case there should be animals correctly described and registered as reds (or as red-and-whites) and as whites, which are genotypically roan and which therefore breed as roans. With these possibilities in mind, then, every anomalous case in our data has been care- fully examined. The progeny of the tmexpected animal i~seLfand of both its sire and dam have been traced in the herd-books wherever possible and in nine of the eleven cases recorded one or other of the three animals u~der consideration has been found from its I. Ct[ES~X JoH~,s 159 breeding record to be genotypieally roan although not registered as such. In the other two cases the necessary data were not available. A detailed analysis of the eleven anomalous cases is given below. A~otc. In animals marked * the eolour h~ been checked from the animal itself. In those marked ~ the colour has been checked from photographs only. The number of an a~LimaI (and the volume and page number), refers to Coates's Shorthorn Herd-Book in which ~ British Pedigree Shorthorns are registered, giving, in~r alia, parentage and colour. In the herd-books all males have numbers by which they caaa be traced. Until recently, however, females were no~ numbered, so that in referring to dams of an earlier date it is necessary to give the volume and page for hard.book reference. The number of a male is always placed after the name, the number of a female, if p~ent, is in front of the nsz.ue. For ease of reference the hard-book practice has been followed in this paper, although it gives a suggestion of inconsistency in nommmtature.

Case t. ~ed-and-littte-white x ~oan gave white: Hill Victor, T 190767 (red-and-tittle-white) l 2980, Haining ~, aterlo'o* (roan) ) Eaton Waterloo Swell,* 215328 (white)

_All the recorded matings of these animals were examined, and it was found that Haining Waterloo, with two additional rantings, and Eaton Waterloo Swell, with three recorded rantings, were concerned in no exceptional results. Hill Victor, however, gave twenty- eight re~stered offspring, and of these eight were anomalies if he were red-and-white. All would be normal if he were roan, except one which is equally anomalous whether he were roan or red-and-whi~e: mated to a white (320022-Pearl Lady) he gave a red-and- little-white (92995 Kid~side Pearl). Pear1 Lady gave only one other registered offspring and this was unexceptional. There are no recorded offspring of Kidside Pearl so that no light can be thrown on her constitution.

Case 2. ~,ed • red gave roan : Ireby Warrior,l" 223955 (red)t 122976, Woodhull Grey* (roan) 87148, Wreay Grey 12th (red) J Only one other mating of Wreay Grey 12th could be traced and four of Woodhull Grey. All gave unexceptior~al results. Ireby Warrior: however, gave two anomalies in nine~en makings. Seventeen of these rantings were of such a type that the recorded results were equally to be expected whether he was roan or red, but in the other two, wlfich alone were specific, he act.ed as a roan.

Ca.~e. 3. I~,.ed • red gave roan: Eaton Stifling Prince,t 180549 (rzd)] 8982, Eaton Princess Gift'~ (red) ~ 79178, Woodhull Priucess Gift t (dark roan)

Woodhnlt Princess Gift gave six calves, Eaton Princess Gift gave an additiona.l t;we]ve; none of I~hese were ano:m~l.lohs. Eaton Stifling Prince produced twenty-six offspring, twenty, four of which were unexceptional whether he was red or roan. The remaining two were normal if he were roe.n, anomalous if he were red--mated to ,~ red he gave roan, mated to a whi~e he gave a white.

Case ,1. Red x roan gave whi~e: Kehnscott Acrobat 4th, 126217 (red)} Orange 52rid: t V. 64, p. 993 (roan) I Kelmscott Conjurer 56~h,~- 181977 (white) 160 Inheritance of coat colour in dai W shorthorn cattle Kelmscott Coniurer 56th gave no exceptions ia foul"~een m~tin~ and Orange 52nd, in five other rantings which were ~aced, gave only normal results. Kelmscott .~_crobat 4-th gave 126 recorded offspring, but in 116 matmgs only could the eolour of the dam be found. If he were a red, as registered: then eight of the 116 matmgs produced anomalous off- spring. All were normal if he were roan. ~[n the rmnainiug 108 he could have been either roan or red. Case 5. Red x red-and-white gave roan: Lawnhead Cavalier,~ 182413 (red) ] 438336, Duchess of Ranton 6th? ~13833, Duchess of Ranton 3rd$ (red-and-white)~ (red roan) No offspring of Duchess of Ran~on 6th could be traced. Lawnhead Cavalier gave no other exceptions in eight recorded marinas. Duchess of Ranton 3rd, however, produced four offspring, two of which were anomalous if she were a red-and-white as registered, but all would be normal if she were a roan. Case 6. Red x red-and-white gave roan: Vestris Duke, 113607 (red) ] Rosamund of Chesterton 2nd, V. 61, Rocks Cup/[ V. 58, p. 439 (red-and-whi~e)y p. 642 (roan) No offspring of Rosamund of Chesterton 2nd could be traced. Vestris Duke gave nine additional recorded offspring, all of which were unexceptional. Rocks Cup, however, with four recorded offspring, produced two which were anomalous in coiotur if she were red- and-white but all would be normal if she were roan. Case 7. Red x red-andqittle-white gave roan : Longhills Cotmt,j" 116262 (red) ~ Preshnte Dolphin, 127358? Dolphinlee Flora:~ V. 58, p. 683 (red-and-little-white)~ (dark roan) DotphinIee Flora gave two exceptional results in seven rantings. All would be normal if she were roan. Preshute Dolphin produced nineteen offspring, none of which were anomalous. Only one other mating of Longhills Cotmt could be traced, this being un- exceptional. Case 8. Red • white gave red: Bessie's Champion,~ 1784jJ8 (white)l Duchess ll8th, V. 61, p. ~67 fled) J 37090, Duchess 210th-~ (red) Only one other mating of Bessie's Champion could be traced, and the result of this was Lmexceptional. Duchess 178th gave three other recorded offspring all of which were normal. Duchess 210th, however, gave four offspring, two of which were anomalous if she w~re red, as registered, but all would be normal if she were roan. Case 9. Red-and-white x red gave roan: Upton Lord Waterloo 2nd, 14-6048 (red-and-whi~)~ Kenilworth Dairymaid 2nd:j" Kenilworth Dairymaid, V. 64, p. 1'4.0 (red) ) V. 64, p. 740 (roan) Of the four rantings of Kenilworth Dairymaid, two produced anomalous offspring and indicated she was breeding as a roan. Kenilworth Dairymaid 2nd gave six unexceptional offspring, breeding according to her registered colour. No o~her rantings of Upton Lord Waterloo 2nd could be t.racefJ. I. CrS_~S~ER JoN~s 161 Case 10. Red-and-little-white x red-and-little-white gave roan: Snowdon Boy, 145575 (red-and-little-white) l Queen of the West, V. 67, Queen of France, y. 60, I). 1058 (red-and-little-white)j p. 526 (dark roan) Queen of France gave five other offspring, Queen of the West gave two, and all were unexceptional. No further matiugs of Snowdon Boy could be traced. Case 1I. Red-and-white • red-and-little-white gave roan: Plus Power General, 11~t999~ (red-and-white) ~ Plus Power Eyebright, Wild Eyebright ]lth, V. 56, p. 1135 (red-and-litth-white)J V. 61, p. 736 (dark roan) Wild Eyebright 11th gave three other offspring and Plus Power Eyebright gave seven offspring, all of which were unexceptional. No further marinas of Plus Power General could be traced. Thus in nine of the eleven anomalous cases examined above the une~q)ected animal itself or its sire or its dam has been found to be breeding as roan though registered as red or as red-and-white, so that the anomalies depend simply upon the mistaken identity of certain genotypic roans. In the two remaining cases the necessary data are not available. In the present data there is an unusually tow percentage of exceptions in the records-- only 1-2 % as compared with an average of 5-8 % (Smith, 1925, consolidated data), and this is probably due to the fact that one particular herd has been studied which is in the hands of an exceptional] L careful recorder (Mr Hamilton). Even so there is one animal in the present herd which is known to have been wrongly described, Eaton .Winsonia 13th, V. 87, p. 873, registered as a red-and-white was later found-to be a dark roan. _Mad perhaps some of the nine animals under discussion may similarly have been wrongly described. Eaton Stifling Prince, however (Case 3), is ahnost certainly correctly described as red. Mr Hamilton knew him we]l; he was in the Eaton Herd for many years and was a noted champion. It is practically impossible that h.e was wrongly registered. Walther (1913) records two similar cases, and these three appear to be examples of animals which though genotypically roan, are phenotypically truly red. There are no cases in our data of genotypic roans being registered as whites, but from the literature it is evident that such cases do occur. Wentworth (1913) reports one case of wrong description, a very light roan which was registered as a white. And Walther (1913) records one white which, on most careful inquiry from the b:reeder, seemed to be really ~-hite yet bred as a roan. So that at the white end of the roaning series, a.s welt as at the red: roan seems to pass imperceptibly into self-eolour, and this is probably the exl?]al,a.tion of most of the exceptions on record. It. is doubtful whether it is the full explanation of the much-discussed white bulls, which, mated to red cows, have given a considerable proportion of red offspring. Laughlin (1911.) rec.ol:ds one such bull which, mated to reds, gave forty~one roan,% nine reds and four recl.-a.nd whiter; mated to a. ~:oan he gave one white, Lloyd .Yeats & Evvard (]9t6) record a white bull, Whitehall Sultan, 16.3573,:~ which, mated to reds, gave foI'~y-four roans and fifteen l"eds. Smith (1925), quoting from the unpublished data of l~Iartini, records another white bull, Maxwalton Sultan, 305870,~ son of Whitehall Sultan, which, mated to reds, gave forty-one roans, t.hirteen reds and two whites. Smith, ]?ointiu.g ottt

++ American Herd-Books. 162 Inheritance of coat colour in dairy shorthorn cattle the difficulty, which sometimes occurs, of distinguishing a red roan from a red, suggest,s that the thirteen reds were probably red roans, and that the two whites were herd-book errors or mutations. His suggestion of wxong description demands an error in registration of ~bout 25 ~/o, yet he states that Marthfi had sough~ for cases of" mtsregistratioa among the offspring of MaxwalVon Suttan but had found none. Ibsen (1933), referring ~o the cases of }~naitehalI Sultan and Maxwalton Sultan, postulates, in Short:horns, a roan modifier, rm, a rare recessive which, when present in the homozygous condition, changes roan to red. But Whitehall Sultan, if he were homozygous for rm, must have met at least fifteen cows homozygous for rrn--if he were heterozygous for the factor he must have met somethfllg tike thirty homozygous for rm--out of fifty-nine. If he were heterozygous for rm and the cows heterozygous, then practically all must have carried it to give fifteen rmrm in fifty-nine rantings, get Ibsen suggests it as a rare recessive. If it were as common as it would have to be to give the result~s recorded for Whitehall Sultan and Maxwalton Sultan its incidence would give results in the general population entirely at variance with the observed facts of inheritance; for: however it may be interpreted, red x white ~ves roan in an overwhelmingly high proportion of oases. It seems more probable that Whitehall Sultan and )'Iaxwalton Sultan and other similar anomalous white btdls refen'ed to in ~he literature were, in fact, genotypio roans which were phenotypicalty at the extreme white end of the series. (The two whites among the offspring of Maxwalton Sultan would still be exceptional even though he were breeding as a roan--units both they ,~md he were extremely white roans.) The only difficulty in a.ccepting this explana- tion is that, where the details of ~he progeny are recorded, the proportion of roans to reds is very high. The numbers are small and may have no significance bat the results in the three cases are surprisingly similar.

V. GRADES OF eO~tNIh"G There remains for discussion the possible causes behind the various grades of roaning. White spotting may sometimes add ~o the whiteness of ~ roan, but it could never seriously ma~k the degree of roaning. In the Eaton Herd, at least, white spotting is mainly ventral in distributionj so that when present to its me'mum extent it does not involve the dorsal half of the animal except sometimes across ~.he shoulders and the forehead. So that the grade of roaning of an animal can be judged quite apart from any consideration of the areas subject to white spotting. Wright (1917) suggested that the various grades migk~ be given by a series of multiple aIlelomorphs, producing different strengths of white. That this is not the case is shown by the fact that a roan, mated to reds, gives many different grades of roan. One example is shown in P1. 7, figs. 1a-16. The sire, Eaton Rose King, 207056 (fig. 13), mated to reds gave red (fig. 14:), medium roan (fig. 15) and iight roan (fig. 16), as well as many in~er- mediate grades. Clearly this ~ not a case of multiple allelomorphs. Crew (1925) suggested that possibly there are modifying factors. There is no evidence for specific modifying genes and tmtil such evidence is forthcoming it seems better no~ to postulate them. It appears that, in different internal environments, red and white express themselves in varying degrees--beyond that it seems unsafe to go. I. CI=I.ESTER ~IONES 163

~UMk~AP.Y ]. Inherit~nce of red, white and roan in Shorthorn cattle is best explained on Ibse~'s 1933 theory that red (R) is hypostatic and }mmozygous in all Shorthorns, and tha~ whit~ is due to a factor (N) which in the heterozygote gives roan. 2. Recorded exceptions to the main plan of inheritance are explained by the fact that genotypic roan extends from complete red to complete white in the phenotype.

The author wishes to express his thanks to Mrs R. C. Bisbee (Ruth C. Bamber) for her continued help and criticism throughout the investigation and to Mr Pakenham Hamilton, the Bailiff of the Duke of Westmmstcr's farms, who gave access to the herd of pedigree Shorthorn cattle and whose private records and practical help were invaluable.

R EFEICENCES BoG~T, 1~. & L~sl;.w.H.L. (1937). The relation of lmir and skin pigmentation tr colour in cattle, with some notes on gulnea-pig hair pigmentation. J. GeT,cA.35, 31-60. Ch~w, F. A. ]5.. (192~5). AniTn~d GtT~e~ic.s. Edinburgh. Dgcx, R. W. (1923). Colours of Shorthorn cattle. J. itered. 14, 65-75. ]~v't-,uRO, J. i'~., SHEAI~ER, P. S., LINDSTROI~, E. W. & S.~II"rH,A. D. B. (1930). Tlm inheritance of coiour and horns in blue-gray cattle. 2. Rea. BtdL In. Ag,ic. Exp. Sta. no. ].33, pp. 1-16. Gow~, J. W. (1927). A resumtl of cattle hflaeritance..BibIiogr, g~7~d. 3, 87-137. IBsz~, H. L. (1933). Cattle fl~heritance. I. Colour. Oenaics, :18, 441-80. LxvGln_nr H. H. (1911, 1912). The il~eritance of colo~tr and honls in Shorthorn cattle. Amer. W'at. 4,,5, 70'5--42 and 46, 5-28. LLoyn JOh'F~S, O. & EVV~D, J. (1916). Inileritance of colour and horns in blue-gray cattle. Res. ]3~dl, In. Agric. Exp. Sta. no. 30, pp. 67a-106a. I~OBm~TS, E. (1937). Colour inheritance in Shorthorn cattle. J. Hersd. 28, 167-8. S~:rr~, A. D. B. (1925}. Shorthorn colout~. J. Hered. ~[6, 73-84. W~L~r-~r., A. ~. (1913). Die Verebung unpigmentierter Ha~,re (Schimmehmg) und H:mt,s~ellen ('ab- zeiohe~ ') bei Rh~d und Pferd als Beispefle transgreasiv fluctm'ieuder Faktorcn. Z. induk~ Abstamm.-u. VercrbI_~,e, lO, 1-48. WS~'u'WO~Ta, E. N. (1913). Colour in Shorthorn cattle. Ame~'. Bre,,zl. Mug. 4, 202-8. Wmsox, J. (1908). Mendelians eharactvrs among Shorthorn catdc. Sci. Proc. D~bli~ Sac. li (N.S.), 317-24. Wr.mwr, S. (1917). Colour inheritance h~ mammals. VI. Cxtttle. J. Hered. 8, 521-7.

EXPI,ANA']'I.ON OF PLATLS 6 AND 7

P~AT~ 6 F~gs. 1-12. Photograph.s showing different grad~ of roa,d:lg, from durh ro~n (fi~. 1) to light roan (fig. 12). I:'L_~TE 7 Photographs showing i,Jaton Rose King, 207056, and thrcc of his off.~ln'ing fi'om red cows. :Fig. 13. Eaton P,o~c King. 207056, ro:m. Fig. ]5. Medium roan. Fig. 14. P~d. Fig. 16. Light roan. ,JOURNAL OF GENETIC8, u 4-8, NO, 2

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