L’autisme est un trouble neurodéveloppemental précoce et pervasif présent, environ, dans 1 % de la population infantile. Caractérisé par un phénotype extrêmement hétérogène, il comprend un déficit de l’interaction sociale, de la communication et la présence de comportements répétitifs et stéréotypés. Les premières études effectuées sur les jumeaux ont été fondamentales pour la démonstration des bases génétiques des troubles du spectre autistique, dont l’héritabilité est extrêmement complexe et insuffisamment expliquée. Même si des facteurs épigénétiques ont été identifiés comme causes potentielles, les bases neuropathologiques associées restent largement inconnues et l’absence d’un marqueur biologique spécifique rend le diagnostic de ce trouble essentiellement clinique. Les études de neuroimagerie pourraient contribuer à une meilleure compréhension des bases neuroanatomiques même si, actuellement, elles ne sont pas conclusives sur la présence d’anomalies cérébrales structurales ou fonctionnelles spécifiques à l’autisme. Les structures cérébrales sont largement héritables et influencées par des variantes génétiques qui commencent à être clarifiées par des études avec une bonne puissance statistique [2]. Les apparentés des enfants autistes présentent, souvent, des phénotypes intermédiaires entre ceux des cas et des contrôles, sans être atteints eux-mêmes. C’est dans cette optique que l’exploration des phénotypes neuroanatomiques des apparentés est cruciale dans la compréhension de l’association entre génétique, hétérogénéité des différences structurales et différents phénotypes cliniques [1]. On présentera les résultats préliminaires de l’étude des caractéristiques génotypiques, cliniques et neuroanatomiques chez une cohorte de sujets autistes et de leurs apparentés, appareillés à des familles non atteintes, qui a pour objectif de pouvoir contribuer à mieux caractériser cette maladie et ses bases endophénotypiques.

The purpose of this study was the estimation of genetic and phenotypic parameters of important economic traits in Khazak native hens in Iran. The registered records of 7 434 Khazak native chickens containing 5 238 hens and 2 196 cocks in the research centre of Zabol University from 2007 to 2011 were used. The results of this study were compared with the results of studies on other native chickens breeding in Iran (Yazd: 4198, Mazandaran: 49 536, Esfahan: 23 108, West Azarbaijan: 24 890 and Fars: 30 279). Genotypic and phenotypic correlations between traits and heritability of traits were evaluated by univariate and bivariate animal models using ASREML software. The quantity of some traits such as the average egg production, weight of eggs produced, fertility, hatchability, age of sexual maturity and broodiness were a month 120, 45.15 g, 65.25 percent, 74.83 percent, 5.54 and 1.90, respectively. The heritability of sexual maturity age, the number of eggs produced and egg weight were 0.22 ± 0.41, 0.16 ± 0.13 and 0.50, respectively. The genetic correlation between the age of sexual maturity and the number of eggs produced were 0.95 ± 0.02 and 0.29 ± 0.07, respectively. The results of the study showed that decreasing the sexual age of maturity will lead to an increase in the number of eggs produced. The results of variance analysis showed that some factors such as hen age, broodiness (P < 0.01) and the weight of hens have a significant effect on hatchability.

The Nublang is a unique dual-purpose breed of Bos indicus cattle found in Bhutan. They have been crossed with Mithun (Bos frontalis) and Bos taurus breeds in an effort to improve milk production leading to a decline in the population of purebred Nublang. An alternative to crossbreeding would be the genetic improvement of milk yield within purebred Nublang, thus allowing conservation and sustainable utilization of the pure breed. It is important to measure the genetic variability (heritability) of milk yield to assess the potential for genetic improvement within Nublang. Therefore this study estimated phenotypic and genetic parameters of milk yield using 2 052 test day milk yields from 66 cows recorded from 1997 to 2013 in the National Nublang Farm, Tashiyangphu. The average daily milk yield (DMY) was 2.12 ± 0.7 litres (N 2 052, range: 0.3–5.0 L, CV: 34 percent). Parity, month in milk and year all had a significant effect on DMY (P < 0.05). The average lactation milk yield (LMY) was 519.2 ± 151 L (N: 261, range: 115–881.7, CV: 29.1 percent) and average lactation length was 239 days. LMY was significantly influenced by parity (P < 0.05) and season of calving. The heritability of DMY and LMY was 0.22 ± 0.16 and 0.13 ± 0.20, respectively. The repeatability estimates were 0.45 ± 0.05 and 0.49 ± 0.08 for DMY and LMY, respectively. Overall the heritability and repeatability estimates of milk yields indicate potential for genetic improvement of milk yield in Nublang cattle through selection. However, it is recommended that a larger dataset is generated to enable more precise estimates of genetic parameters.

Genealogical and live body weight monthly records from 790 sheep of the Chiapas breed born between 1991 and 2004 were used to characterize the growth curve and estimate (co)variance components for the parameters (A, k and b) of the Gompertz function. The pedigree structure consisted of 790 sheep, including 45 rams and 379 ewes. Estimation of (co)variance components for each growth parameter was achieved using a univariate animal model with the restricted maximum likelihood (REML) method. Estimated values of heritability were: A (adult weight) 0.21 ± 0.06; b (integration constant) 0.25 ± 0.07; k (maturity rate) 0.16 ± 0.06; age at the inflexion estimated as (ln(b)/k) 0.24 ± 0.07; and absolute growth rate as [k*(0.368*A)* ln(A/0.368*A)] 0.22 ± 0.07. The growth of males was 24% (P < 0.05) faster than that of females; adult weight was 25 ± 0.7 kg for males and 23 ± 0.7 kg for females; absolute growth was 59 ± 2 g and 44 ± 2 g per day for males and females respectively. The Chiapas breed of sheep is a small animal with a slow growth curve, probably due to its adaptation to the environmental conditions where it lives. Growth curve can be modified through selection.