Avaliação genética da pelagem de cães da raça Dálmata / Genetic evaluation of the coat of dogs of the Dalmatian breed

A raça Dálmata é uma das raças mais populares, e, de acordo com seu padrão racial, deve apresentar cor de pelagem branca, com pintas pretas ou fígado. Vários loci estão envolvidos na determinação da cor da pelagem dos cães. No Dálmata, os principais são o locus B e o locus E, pois esses lócus têm influência um sobre o outro, causando uma interação gênica chamada epistasia, onde o efeito de um gene modifica o efeito de outro, alterando o fenótipo do animal. Com o avanço da cinofilia, o melhoramento genético em cães se tornou mais importante, tornando o conhecimento desses genes uma ferramenta necessária para os criadores. O objetivo deste trabalho foi demonstrar a importância do teste genético para o gene E, e seu auxílio no planejamento de acasalamento nos canis de Dálmatas. Para isso, foi usada uma ninhada nascida em Fortaleza, na qual foram realizados testes genéticos para o gene E do padreador de pintas pretas e de dois filhotes escolhidos aleatoriamente, um preto e um limão. O teste foi realizado através da técnica de PCR, e como resultado foi visto que o pai é heterozigoto (Ee). Já em relação as crias, foi confirmado o homozigoto dominante (EE) para a cria dentro do padrão e o homozigoto recessivo (ee) para a cria limão. Nesta cria ocorreu a epistasia, fazendo com que apresentasse pintas alaranjadas. Assim, conclui-se que não se pode definir o genótipo apenas pelo fenótipo, tornando o teste genético uma importante ferramenta para escolha dos padreadores.

The Dalmatian breed is one of the most popular breeds, and, according to its racial pattern, should have a white coat color with black spots or liver. Several loci are involved in determining the coat color of dogs. In the Dalmatian, the major are the locus B and the locus E, because these locus have influence on each other, causing a genetic interaction called epistasis, where the effect of one gene modifies the effect of another, altering the phenotype of the animal. With the advancement of cynophilia, genetic improvement in dogs has become more important, making knowledge of these genes a necessary tool for breeders. The objective of this work was to demonstrate the importance of the genetic test for gene E, and its aid in the planning of mating in dalmatians kennels. For this, a litter born in Fortaleza was used, in which genetic tests were performed for the E gene of the black-spotted and two randomly selected puppies, one black and one lemon. The test was performed using the PCR technique, and as a result it was seen that the parent is heterozygous (Ee). In relation to the offspring, the dominant homozygous (EE) was created for the offspring and the recessive homozygote (ee) for the offspring. In this breed epistasis occurred, causing it to present orange spots. Thus, it can be concluded that the genotype can not be defined only by the phenotype, making the genetic test an important tool for the selection of stud holders.

Avaliação genética da pelagem de cães da raça Dálmata / Genetic evaluation of the coat of dogs of the Dalmatian breed

A raça Dálmata é uma das raças mais populares, e, de acordo com seu padrão racial, deve apresentar cor de pelagem branca, com pintas pretas ou fígado. Vários loci estão envolvidos na determinação da cor da pelagem dos cães. No Dálmata, os principais são o locus B e o locus E, pois esses lócus têm influência um sobre o outro, causando uma interação gênica chamada epistasia, onde o efeito de um gene modifica o efeito de outro, alterando o fenótipo do animal. Com o avanço da cinofilia, o melhoramento genético em cães se tornou mais importante, tornando o conhecimento desses genes uma ferramenta necessária para os criadores. O objetivo deste trabalho foi demonstrar a importância do teste genético para o gene E, e seu auxílio no planejamento de acasalamento nos canis de Dálmatas. Para isso, foi usada uma ninhada nascida em Fortaleza, na qual foram realizados testes genéticos para o gene E do padreador de pintas pretas e de dois filhotes escolhidos aleatoriamente, um preto e um limão. O teste foi realizado através da técnica de PCR, e como resultado foi visto que o pai é heterozigoto (Ee). Já em relação as crias, foi confirmado o homozigoto dominante (EE) para a cria dentro do padrão e o homozigoto recessivo (ee) para a cria limão. Nesta cria ocorreu a epistasia, fazendo com que apresentasse pintas alaranjadas. Assim, conclui-se que não se pode definir o genótipo apenas pelo fenótipo, tornando o teste genético uma importante ferramenta para escolha dos padreadores.(AU)

The Dalmatian breed is one of the most popular breeds, and, according to its racial pattern, should have a white coat color with black spots or liver. Several loci are involved in determining the coat color of dogs. In the Dalmatian, the major are the locus B and the locus E, because these locus have influence on each other, causing a genetic interaction called epistasis, where the effect of one gene modifies the effect of another, altering the phenotype of the animal. With the advancement of cynophilia, genetic improvement in dogs has become more important, making knowledge of these genes a necessary tool for breeders. The objective of this work was to demonstrate the importance of the genetic test for gene E, and its aid in the planning of mating in dalmatians kennels. For this, a litter born in Fortaleza was used, in which genetic tests were performed for the E gene of the black-spotted and two randomly selected puppies, one black and one lemon. The test was performed using the PCR technique, and as a result it was seen that the parent is heterozygous (Ee). In relation to the offspring, the dominant homozygous (EE) was created for the offspring and the recessive homozygote (ee) for the offspring. In this breed epistasis occurred, causing it to present orange spots. Thus, it can be concluded that the genotype can not be defined only by the phenotype, making the genetic test an important tool for the selection of stud holders.(AU)

Biopsy of bovine embryos produced in vivo and in vitro does not affect pregnancy rates.

Assisted reproductive techniques have significantly contributed to animal breeding programs. Similarly, genomics has provided important information and tools to improve the accuracy of selection. However, the greatest benefits of those tools can only be expected when they are combined, allowing animals to be selected accurately early in life. Therefore, obtaining DNA samples from embryos without compromising their viability is essential for the consolidation of preimplantation genomic selection. We aimed to evaluate the effect on the gestation rate of conducting a biopsy of in vivo (VV) and in vitro-produced (IVP) bovine embryos. The VV and IVP embryos were distributed into two groups: VV-B (biopsied embryos; n = 380) and VV-C (intact embryos-controls; n = 229) and IVP-B (biopsied embryos; n = 91) and IVP-C (intact embryos-controls; n = 227), respectively. After biopsy, embryos from both groups VV-B and IVP-B were cultured for an additional 3 hours before being transferred to synchronized recipients. To evaluate the quality of the DNA obtained in the biopsies, this was used to determine the sex of embryos by polymerase chain reaction. No effect (P > 0.05) of the biopsy was observed for any of the treatments, the pregnancy rate at D 60 post-transfer being similar for VV-B: 206/380 (54.21%) and VV-C: 128/229 (55.89%) and for IVP-B: 24/91 (26.37%) and IVP-C: 45/227 (19.82%). Also, no effect (P > 0.05) of the embryo's stage of development was detected on percentage of pregnant recipients when in vitro embryos were transferred. From the biopsies analyzed, about 90% had the sex determined, confirming that DNA was there and it was efficiently amplified. The results indicated that biopsy does not affect the viability of IVV and IVP bovine embryos and can be used in commercial programs to associate assisted reproductive technologies with genomic selection.

Genetic profiles of Mycobacterium bovis from a cattle herd in southernmost Brazil / Perfis genéticos de Mycobacterium bovis em um rebanho bovino no extremo sul do Brasil

Mycobacterium bovis is the agent of bovine tuberculosis, a disease endemic to all Brazilian states. Molecular typing techniques help to stratify and refine data, providing information that facilitates epidemiological research. In this study, MIRU-VNTR, targeting 24 loci, was employed to identify and characterize the genetic groups of M. bovis isolates obtained from an outbreak of bovine tuberculosis. Eighteen acid-fast bacilli isolates, obtained from bovine tissue samples, and reactive to the comparative cervical tuberculin test, were identified as species of the M. tuberculosis complex, and were genotyped by MIRU-VNTR with 24 primer pairs. Genotyping revealed three genetic profiles comprising one with 15 isolates (83.3%), one with two isolates (11.1%), and one profile with one unique isolate (5.6%). This distinction was achieved with the MIRU 31 primer, which resulted in clustering of two isolates into the same profile, and ETR A, B, and C, which discriminated the isolate with a unique profile. The occurrence of clustered isolates is indicative of recent transmission, whereas isolates with a unique profile suggest reactivation of latent infection. The presence of different M. bovis genotypes in the same herd suggests movement of infected animals or different sources of intra-herd infection. Use of the MIRU-VNTR molecular epidemiology technique in M. bovis isolates obtained from an outbreak of bovine tuberculosis in Rio Grande do Sul state demonstrated the genetic diversity of circulating strains, despite the presence of a predominant group.

Mycobacterium bovis é o agente da tuberculose bovina, enfermidade endêmica diagnosticada em todos os estados brasileiros. As técnicas de tipagem molecular auxiliam a estratificar e refinar dados, fornecendo informações que facilitam as atividades epidemiológicas. Neste estudo aplicou-se a técnica MIRU-VNTR com 24 loci para caracterizar e identificar os agrupamentos genéticos de isolados de M. bovis oriundos de um foco de tuberculose bovina. Dezoito isolados de bacilos álcool-ácido resistentes, obtidos de amostras de tecido de bovinos reagentes ao teste cervical comparativo e identificados como espécies do complexo M. tuberculosis, foram genotipados por meio de MIRU-VNTR com 24 pares de iniciadores. A genotipagem revelou três perfis genéticos distintos: um para 15 isolados (83,3%); um para dois isolados (11,1%) e, por fim, um isolado com perfil único (5,6%). Os iniciadores responsáveis por essa distinção foram MIRU 31, que agrupou dois isolados em um perfil, e ETR A, B e C, que discriminaram o isolado de perfil único. A ocorrência de agrupamentos de isolados é indicativa de transmissão recente, ao passo que isolados de perfil único sugerem reativação de infecção latente. A presença de diferentes genótipos de M. bovis no mesmo rebanho sugere haver circulação de animais doentes ou existirem diferentes fontes de infecção intrarrebanho. A aplicação da técnica de epidemiologia molecular MIRU-VNTR a isolados de M. bovis obtidos a partir de um foco de tuberculose bovina no Rio Grande do Sul demonstrou haver diversidade genética entre as estirpes em circulação, embora exista um agrupamento predominante.

Genetic profiles of Mycobacterium bovis from a cattle herd in southernmost Brazil / Perfis genéticos de Mycobacterium bovis em um rebanho bovino no extremo sul do Brasil

Mycobacterium bovis is the agent of bovine tuberculosis, a disease endemic to all Brazilian states. Molecular typing techniques help to stratify and refine data, providing information that facilitates epidemiological research. In this study, MIRU-VNTR, targeting 24 loci, was employed to identify and characterize the genetic groups of M. bovis isolates obtained from an outbreak of bovine tuberculosis. Eighteen acid-fast bacilli isolates, obtained from bovine tissue samples, and reactive to the comparative cervical tuberculin test, were identified as species of the M. tuberculosis complex, and were genotyped by MIRU-VNTR with 24 primer pairs. Genotyping revealed three genetic profiles comprising one with 15 isolates (83.3%), one with two isolates (11.1%), and one profile with one unique isolate (5.6%). This distinction was achieved with the MIRU 31 primer, which resulted in clustering of two isolates into the same profile, and ETR A, B, and C, which discriminated the isolate with a unique profile. The occurrence of clustered isolates is indicative of recent transmission, whereas isolates with a unique profile suggest reactivation of latent infection. The presence of different M. bovis genotypes in the same herd suggests movement of infected animals or different sources of intra-herd infection. Use of the MIRU-VNTR molecular epidemiology technique in M. bovis isolates obtained from an outbreak of bovine tuberculosis in Rio Grande do Sul state demonstrated the genetic diversity of circulating strains, despite the presence of a predominant group.(AU)

Mycobacterium bovis é o agente da tuberculose bovina, enfermidade endêmica diagnosticada em todos os estados brasileiros. As técnicas de tipagem molecular auxiliam a estratificar e refinar dados, fornecendo informações que facilitam as atividades epidemiológicas. Neste estudo aplicou-se a técnica MIRU-VNTR com 24 loci para caracterizar e identificar os agrupamentos genéticos de isolados de M. bovis oriundos de um foco de tuberculose bovina. Dezoito isolados de bacilos álcool-ácido resistentes, obtidos de amostras de tecido de bovinos reagentes ao teste cervical comparativo e identificados como espécies do complexo M. tuberculosis, foram genotipados por meio de MIRU-VNTR com 24 pares de iniciadores. A genotipagem revelou três perfis genéticos distintos: um para 15 isolados (83,3%); um para dois isolados (11,1%) e, por fim, um isolado com perfil único (5,6%). Os iniciadores responsáveis por essa distinção foram MIRU 31, que agrupou dois isolados em um perfil, e ETR A, B e C, que discriminaram o isolado de perfil único. A ocorrência de agrupamentos de isolados é indicativa de transmissão recente, ao passo que isolados de perfil único sugerem reativação de infecção latente. A presença de diferentes genótipos de M. bovis no mesmo rebanho sugere haver circulação de animais doentes ou existirem diferentes fontes de infecção intrarrebanho. A aplicação da técnica de epidemiologia molecular MIRU-VNTR a isolados de M. bovis obtidos a partir de um foco de tuberculose bovina no Rio Grande do Sul demonstrou haver diversidade genética entre as estirpes em circulação, embora exista um agrupamento predominante.(AU)

Setting up equine embryo gender determination by preimplantation genetic diagnosis in a commercial embryo transfer program.

Preimplantation genetic diagnosis (PGD) allows identifying genetic traits in early embryos. Because in some equine breeds, like Polo Argentino, females are preferred to males for competition, PGD can be used to determine the gender of the embryo before transfer and thus allow the production of only female pregnancies. This procedure could have a great impact on commercial embryo production programs. The present study was conducted to adapt gender selection by PGD to a large-scale equine embryo transfer program. To achieve this, we studied (i) the effect on pregnancy rates of holding biopsied embryos for 7 to 10 hours in holding medium at 32 °C before transfer, (ii) the effect on pregnancy rates of using embryos of different sizes for biopsy, and (iii) the efficiency of amplification by heating biopsies before polymerase chain reaction. Equine embryos were classified by size (≤300, 300-1000, and >1000 µm), biopsied, and transferred 1 to 2 or 7 to 10 hours after flushing. Some of the biopsy samples obtained were incubated for 10 minutes at 95 °C and the rest remained untreated. Pregnancy rates were recorded at 25 days of gestation; fetal gender was determined using ultrasonography and compared with PGD results. Holding biopsied embryos for 7 to 10 hours before transfer produced pregnancy rates similar to those for biopsied embryos transferred within 2 hours (63% and 57%, respectively). These results did not differ from pregnancy rates of nonbiopsied embryos undergoing the same holding times (50% for 7-10 hours and 63% for 1-2 hours). Pregnancy rates for biopsied and nonbiopsied embryos did not differ between size groups or between biopsied and nonbiopsied embryos within the same size group (P > 0.05). Incubating biopsy samples for 10 minutes at 95 °C before polymerase chain reaction significantly increased the diagnosis rate (78.5% vs. 45.5% for treated and nontreated biopsy samples respectively). Gender determination using incubated biopsy samples matched the results obtained using ultrasonography in all pregnancies assessed (11/11, 100%); untreated biopsy samples were correctly diagnosed in 36 of 41 assessed pregnancies (87.8%), although the difference between treated and untreated biopsy samples was not significant. Our results demonstrated that biopsied embryos can remain in holding medium before being transferred, until gender diagnosis by PGD is complete (7-10 hours), without affecting pregnancy rates. This simplifies the management of an embryo transfer program willing to incorporate PGD for gender selection, by transferring only embryos of the desired sex. Embryo biopsy can be performed in a clinical setting on embryos of different sizes, without affecting their viability. Additionally, we showed that pretreating biopsy samples with a short incubation at 95 °C improved the overall efficiency of embryo sex determination.

Impacto da utilização da somatotropina bovina (bST) sobre a produção de leite e a avaliação genética de bovinos da raça holandesa / Impact of bovine somatotropin (bST) on the milk production and genetic evaluation of Holstein cattle

O objetivo do presente trabalho foi estudar a influência do uso da somatotropina bovina (bST) sobre a produção de leite (PL305) e a avaliação genética da PL305 de bovinos da raça Holandesa. Foram utilizados dados referentes a 474 touros e observações referentes a 3341 lactações de 1271 vacas, durante o período de 1999 a 2003. A análise de variância foi realizada pelo procedimento GLM do SAS (2003) e os parâmetros genéticos sob modelo animal unicaracterístico. As estimativas de herdabilidades para o modelo 1 (bST como efeito fixo) e modelo 2 (ausência desse efeito) foram respectivamente de 0,26 e 0,23 e a correlações entre os valores genéticos preditos para os conjuntos de touros a (todos avaliados), b (os melhores 20% ), c (os melhores 10%) e d (os melhores 5%) foram, respectivamente, 0,9484, 0,9829, 0,9752 e 0,8974. A análise de variância demonstrou que as médias de PL305 aumentaram significativamente (P<0,0001), com aumento do número de aplicações do bST. As altas correlações de Spearman entre os valores genéticos dos touros, considerando-se ou não o uso do bST no modelo, indicam que o uso desta tecnologia não interfere na classificação dos touros avaliados geneticamente.

The objective of this work was to study the influence of the use of bovine somatotropin (bST) on milk yield (MP305) and genetic evaluation of MP305 of Holstein Cattle. Data from 474 bulls and observations concerning 3.341 lactations of 1.271 cows during the period from 1999 to 2003 were used. Variance analysis was performed by the GLM SAS procedure (2003) and parameters in one animal model. The heritability estimates for model 1(bST as a fixed effect) and model 2 (absence of this effect) were respectively 0.26 and 0.23 for the two analyses and correlations between estimated breeding values for bulls sets a (all evaluated), b (best 20%), c (best 10%) and d (best 5%) were, respectively, 0.9484, 0.9829, 0.9752 and 0.8974. Variance analysis of variance showed that the average PL305 increased significantly (P<0.0001) with the increase number of bST applications. The Spearman correlations coefficients between breeding values of bulls were high, with or without the use of bST in the model, indicating that the use of this technology does not affect the classification of genetically evaluated bulls.

DNA microsatellites for genetic identification in Brazilian Murrah water buffaloes / Uso de microssatélites para identificação genética de búfalos brasileiros da raça Murrah

Brazilian water buffalo (Bubalus bubalis) population is currently approximately 3,000,000. Despite of this fact, genealogical control is still one of the problems of the Brazilian selection and breeding programs. The DNA test is important to develop a system that allows the animal genealogy certification as well as its undeniable individual and parentage identification. The present study was performer by using a panel of 14 microsatellites markers in Brazilian Murrah buffaloes (n=100) in order to estimate the genetic variability and calculate the parentage exclusion probability. A total of 92 alleles were detected in the whole sample and the number of alleles varied from one (locus D5S2) to 13 (locus CSSM47). The Polymorphism Information Content values ranged from 0.00 (locus D5S2) to 0.845 (locus BM1706). Heterozygosity values ranged from 0.00 (D5S2) to 0.861 (BM1706). The paternity exclusion probabilities when only one and both parents were analyzed was 0.985424 (PE-1) and 0.999541 (PE-2), respectively. Observed a probability of exclusion of 0.999998% when both parents (PE-3) were tested for the set of 14 microsatellites. This panel is already used in Italy for the Mediterranean buffaloes, one of the four breeds raised in Brazil. However, it is highly recommended that new loci are analyzed in order to increase the microsatellites panel repertoire used for genealogical studies.

Atualmente, o tamanho do rebanho bubalino brasileiro (Bubalus bubalis) é de cerca de 3.000.000. Apesar deste fato, o controle genealógico ainda é um dos problemas em programas brasileiros de seleção e de melhoramento animal. O teste de DNA é importante para que se possa desenvolver um sistema que permita a certificação genealógica, bem como as inegáveis identificações individuais e de paternidade. O presente estudo teve como objetivo avaliar um painel de 14 marcadores microssatélites em búfalos brasileiros da raça Murrah (n=100), a fim de se estimar a variabilidade genética, probabilidade de exclusão de parentesco. Foram detectados 92 alelos em toda a amostragem, sendo que o número de alelos variou de um (locus D5S2) a 13 (locus CSSM47). Os valores do Contepudo de Informação Polimórfica variaram de 0,00 (locus D5S2) a 0.845 (locus BM1706). Os valores da Heterozigosidade variaram de 0,00 (locus D5S2) a 0.861 (locus BM1706). As probabilidades de exclusão de paternidade quando apenas um e ambos os pais foram analisados foram de 0,985424 (PE-1) e 0,999541 (PE-2), respectivamente. Foi observada probabilidade de exclusão de 0.999998 quando ambos os pais foram testados (PE-3) para o conjunto dos 14 microssatélites. Este painel já é utilizado na Itália para búfalos, da raça Mediterrâneo, uma das quatro raças criadas no Brasil. No entanto, é altamente recomendável que novos loci sejam analisados a fim de aumentar o painel de microssatélites para estudos genealógicos.

Genetic paternity test for piglets generated by heterospermic cervical and post-cervical artificial insemination / Determinação genética da paternidade em leitões nascidos de inseminação artificial heterospérmica cervical e pós-cervical

Post-cervical artificial insemination (AI) with reduced sperm concentration allows the use of semen from few boars on a high number of females, but the common use of pooled semen in commercial AI programs masks the subfertility of individual boars. This study compared the reproductive performance of post-cervical and cervical heterospermic AI, in commercial farm conditions and through paternity tests. Each AI method was conducted in two groups of 150 sows. Sperm concentration was 3.0 x 109/85mL for cervical AI and 1.5 x 109/60mL for post-cervical AI. Conception and farrowing rates for post-cervical AI (90.7% and 85.3%, respectively) were lower (P<0.05) than for cervical AI (98.7% and 94.7%, respectively). Total litter size did not differ (P>0.05) for post-cervical (12.8 ± 0.3) and cervical AI (13.5 ± 0.3), but it was greater (P<0.05) for parity-two females than for those having 3-5 parities. The paternity test used nine microsatellite markers to genotype 300 piglets from 25 litters, but paternity exclusion was achieved for only 95 piglets, which did not differentiate boars across AI methods.

A inseminação artificial intra-uterina (IAIC) com reduzida concentração de espermatozóides por dose permite que o sêmen de um menor número de reprodutores seja usado em um maior número de fêmeas. Porém, o uso freqüente de pools de sêmen de dois ou mais machos na inseminação heterospérmica pode mascarar o baixo desempenho de alguns reprodutores. O objetivo deste estudo foi comparar o desempenho reprodutivo da IAIU com a inseminação artificial intracervical (IAIC), usando amostras heterospérmicas de sêmen, em condições de rotina de campo e através de teste de paternidade. A IAIC foi feita com 3,0 x 109espermatozóides/85mL e a IAIU foi feita com 1,5 x 109 espermatozóides/60mL, ambas em grupos de 150 fêmeas. A IAIU apresentou taxas menores (P<0,05) de concepção (90,7%) e parição (85,3%) do que a IAIC (98,7% e 94,7%, respectivamente). O tamanho total da leitegada não diferiu (P>0,05) entre IAIC (13,7 ± 0,3) e IAIU (13,0 ± 0,3), mas foi mais alto nas fêmeas de segundo parto do que nas com 3-5 partos (P<0,05). O teste de paternidade usou nove microssatélites para a genotipagem de 25 leitegadas, totalizando 300 leitões, havendo exclusão de paternidade somente em 95 leitões, o que não permitiu diferenciação entre os machos, dentro das técnicas de IA.

Genetic analysis of Holstein cattle populations in Brazil and the United States.

Genetic relationships between Brazilian and US Holstein cattle populations were studied using first-lactation records of 305-d mature equivalent (ME) yields of milk and fat of daughters of 705 sires in Brazil and 701 sires in the United States, 358 of which had progeny in both countries. Components of(co)variance and genetic parameters were estimated from all data and from within herd-year standard deviation for milk (HYSD) data files using bivariate and multivariate sire models and DFREML procedures distinguishing the two countries. Sire (residual) variances from all data for milk yield were 51 to 59% (58 to 101%) as large in Brazil as those obtained from half-sisters in the average US herd. Corresponding proportions of the US variance in fat yield that were found in Brazil were 30 to 41% for the sire component of variance and 48 to 80% for the residual. Heritabilities for milk and fat yields from multivariate analysis of all the data were 0.25 and 0.22 in Brazil, and 0.34 and 0.35 in the United States. Genetic correlations between milk and fat were 0.79 in Brazil and 0.62 in the United States. Genetic correlations between countries were 0.85 for milk, 0.88 for fat, 0.55 for milk in Brazil and fat in the US, and 0.67 for fat in Brazil and milk in the United States. Correlated responses in Brazil from sire selection based on the US information increased with average HYSD in Brazil. Largest daughter yield response was predicted from information from half-sisters in low HYSD US herds (0.75 kg/kg for milk; 0.63 kg/kg for fat), which was 14% to 17% greater than estimates from all US herds because the scaling effects were less severe from heterogeneous variances. Unequal daughter response from unequal genetic (co)variances under restrictive Brazilian conditions is evidence for the interaction of genotype and environment. The smaller and variable yield expectations of daughters of US sires in Brazilian environments suggest the need for specific genetic improvement strategies in Brazilian Holstein herds. A US data file restricting daughter information to low HYSD US environments would be a wise choice for across-country evaluation. Procedures to incorporate such foreign evaluations should be explored to improve the accuracy of genetic evaluations for the Brazilian Holstein population.

Divergence between biochemical and cytogenetic differences in three species of the Callicebus moloch group.

Specimens from three species of the Callicebus moloch group--C. moloch (N = 80), C. brunneus (N = 166), and C. cupreus (N = 23)--were studied. Twenty genetic loci were investigated through electrophoresis, genetic distances were estimated, and the results compared with the available cytogenetic data. Low values of genetic distance were encountered, contrasting with relatively large chromosome differences. We propose that recent karyotypic rearrangements, rather than other Pleistocene events, were the major evolutionary mechanisms determining speciation in these three taxa.