Banca de QUALIFICAÇÃO: ANDREZA CORREIA DA SILVA

Uma banca de QUALIFICAÇÃO de MESTRADO foi cadastrada pelo programa.
STUDENT : ANDREZA CORREIA DA SILVA
DATE: 27/10/2022
TIME: 08:00
LOCAL: Remoto
TITLE:

Genetic Diversity of the Mangalarga Breed

KEY WORDS:

horse, F statistic, coat, pedigree

 

PAGES: 52
BIG AREA: Ciências Agrárias
AREA: Zootecnia
SUBÁREA: Produção Animal
SPECIALTY: Criação de Animais
SUMMARY:

Studies on genetic diversity have been of great importance in breeding programs and conservation of breeds, as they provide information on identification characters of genetically superior animals and on inbreeding, contributing to decision making in relation to genetic management. The objective of the study was to evaluate the genetic diversity within and between different populations of the Mangalarga breed, as well as to describe the organizational structure of the herd. Genealogical information of horses of the Mangalarga breed, born between 1919 and 2018, obtained from the database of the genealogical record system of the Brazilian Association of Mangalarga Horse Breeders (ABCCRM) was used. After excluding inconsistent information, a file was obtained with data from 206,426 animals. To assess the organizational structure of the breed, each Brazilian state where there are records of Mangalarga horses was considered as a subpopulation. The origin and use of the breeders were used as parameters to classify the subpopulations in the following strata: Nucleus, Multiplier I, Multiplier II, Commercial I, Commercial II and Isolated. To assess the genetic variation, we first considered each Brazilian state where there are records of Mangalarga horses as a subpopulation. In a second analysis, the different coats found in the breed were considered as subpopulations. Thus, the Wright fixation indexes were estimated, and the Nei Minimum Distance was used to obtain the genetic distance between the subpopulations. For that, the pedigree data were submitted to the ENDOG 4.6 softwares. In addition, the average relationship coefficient (AR) of each individual in the population was calculated, as well as the inbreeding coefficient (F). Of the 26 Brazilian states, the Mangalarga breed is present in 22 plus the Federal District. Of these, 63.63% were classified as multiplying herds and 36.36% were classified as commercial herds. The estimated mean value for Fis was 0.009379, Fit of 0.010606 and Fst of 0.001239. The average of F for the total population was 2.5%, whereas the AR was 2.29% considering each state a subpopulation. The dendrogram generated from the Nei distance gathered the Brazilian states into two groups with greater genetic dissimilarity, group I was formed by the state of Amapá and group II by the other states. The sorrel coat was responsible for 72.72% of the genetic contribution of all coats. The estimated mean value for Fis was 0.009647, and for Fit it was 0.010641 and for Fst it was 0.001003. The average value of F was 1.03% and the AR was 0.997%, considering each coat a subpopulation. From the dendrogram obtained by the UPGMA grouping method, it was observed that the coats were organized into two large groups with greater genetic similarity, group I was formed by the pampa de sorrel and pampa de preta coats and group II formed by the chestnut, lobuna, pampa de baia, preto, rosilha, tordilha, pampa de tordilha, sorrel sorrel, chestnut pampa and sorrel. It is concluded that the organizational structure of the Mangalarga breed is different from that of most production animals, with no core herd. Inbreeding is under control in the herd. Furthermore, the Fis and Fit fixation indices indicated that there is no excess homozygosity occurring among the subpopulations. The Fst showed that there is low genetic differentiation for the total population.

BANKING MEMBERS:
Presidente - JORGE EDUARDO CAVALCANTE LUCENA
Externa à Instituição - JANAINA KELLI GOMES ARANDAS - UFRPE
Externa à Instituição - LAURA LEANDRO DA ROCHA - UFRPE