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Polymorphisms in mitochondrial DNA (mtDNA) protein- and tRNA-coding genes were shown to be associated with various diseases in humans as well as with production and reproduction traits in livestock. Alignment of full length mitochondria sequences from the 5 known ovine haplogroups: HA (n = 3), HB (n = 5), HC (n = 3), HD (n = 2), and HE (n = 2; GenBank accession nos. HE577847-50 and 11 published complete ovine mitochondria sequences) revealed sequence variation in 10 out of the 13 protein coding mtDNA sequences. Twenty-six of the 245 variable sites found in the protein coding sequences represent non-synonymous mutations. Sequence variation was observed also in 8 out of the 22 tRNA mtDNA sequences. On the basis of the mtDNA control region and cytochrome b partial sequences along with information on maternal lineages within an Afec-Assaf flock, 1,126 Afec-Assaf ewes were assigned to mitochondrial haplogroups HA, HB, and HC, with frequencies of 0.43, 0.43, and 0.14, respectively. Analysis of birth weight and growth rate records of lamb (n = 1286) and productivity from 4,993 lambing records revealed no association between mitochondrial haplogroup affiliation and female longevity, lambs perinatal survival rate, birth weight, and daily growth rate of lambs up to 150 d that averaged 1,664 d, 88.3%, 4.5 kg, and 320 g/d, respectively. However, significant (P < 0.0001) differences among the haplogroups were found for prolificacy of ewes, with prolificacies (mean ± SE) of 2.14 ± 0.04, 2.25 ± 0.04, and 2.30 ± 0.06 lamb born/ewe lambing for the HA, HB, and the HC haplogroups, respectively. Our results highlight the ovine mitogenome genetic variation in protein- and tRNA coding genes and suggest that sequence variation in ovine mtDNA is associated with variation in ewe prolificacy.

Leptin (LEP) is a cytokine-like hormone proven to be involved in diverse biological processes. In livestock, it regulates feed intake, BW homeostasis, and energy balance, among other traits. Natural nonsynonymous genetic polymorphisms in the ovine leptin (oLEP) alter the biochemical and physiological characteristics of its gene products. Here we studied in vitro and in vivo the biochemical and physiological characteristics of recombinant hormones representing the oLEPand bovine leptin (bLEP) reference sequences of wild-type (WT) leptins (GenBank accession No. U84247 and U50365, respectively), oLEP and bLEP recombinant muteins carrying the R4C mutation, and oLEP recombinant hormones carrying the A59V and Q62R mutations, which were detected in bLEP. All proteins were purified to homogeneity as monomers and formed 1:1 molar ratio complexes with the chicken leptin-binding domain (LBD). Surface plasmon resonance experiments revealed that all protein variants exhibit reduced (P< 0.05) affinity to chicken (ch) and human (h) LBD compared with the WT oLEP and bLEP recombinant proteins. The ovine and bovine R4C muteins exhibited significantly (P< 0.05) greater induction of cell proliferation in a Baf/3 cell line bioassay, despite lower affinity toward both hLBD and chLBD. Intra-third cerebral ventricle infusion of oLEP and its 3 muteins in sheep resulted in reduced feed intake. However, the 3 tested muteins had a decreased (P< 0.05) inhibitory effect than the WT LEP. It was concluded that natural genetic polymorphisms in the bLEPare associated with variation in the biochemical and physiological properties of the protein.

The present study was conducted in an Assaf flock in which the FecB (Booroola) mutation was segregated to determine whether the FecB mutation affects birthweight and the pre- and post-weaning growth rate of ewe lambs, as well as the mature bodyweight of ewes. Significant differences (P = 0.01) in birthweight (mean s.e.m.) were found between BB ewe lambs (4.03 0.08 kg) and B+ and ++ ewe lambs (4.16 0.04 and 4.32 0.07 kg, respectively), which themselves did not differ significantly (P > 0.05). An FecB-associated maternal effect on the birthweight of ewe lambs was also detected, with the birthweight of lambs born to BB mothers (3.93 0.08 kg) being significantly (P < 0.0001) different from the birthweight of lambs born to B+ and ++ mothers (4.26 0.04 and 4.33 0.07 kg, respectively), which did not differ significantly. The genotypes of the lambs did not affect their preweaning growth rate. However, the post-weaning growth rate of ewe BB lambs (274 5 g day-1) was significantly (P = 0.05) different from the similar (P > 0.05) post-weaning growth rates of B+ and ++ lambs (284 3 and 290 4 g day-1, respectively). The genotype at the FecB locus also affected the mature bodyweight of ewes, with that of BB ewes (67.3 1.4 kg) being significantly (P < 0.001) different from the similar mature bodyweight of B+ and ++ ewes (70.8 1.1 and 70.1 1.7 kg, respectively).

The studies reported in this paper address the predictions of the social identity model of deindividuation phenomena, or SIDE (Reicher, Spears & Postmes, 1995), concerning the strategic effects of visibility to the in‐group: increasing the visibility of in‐group members to each other increases their ability to support each other against the out‐group and hence increases the expression of those aspects of in‐group identity which would attract sanctions from this out‐group. In a first study, where anti‐fox hunting participants were rendered accountable to pro‐fox hunters, the results were the opposite of those expected: participants actually decreased their endorsement of anti‐hunt disruption (which had been defined as normative for the in‐group but unacceptable to the out‐group) when made more visible to the in‐group. These results were explained by arguing that participants perceived the intergroup relationship as participants versus experimenters rather than as anti‐versus pro‐fox hunters and that in‐group visibility was being used to resist an experimentally imposed definition of themselves as favouring disruptive activity. This interpretation was supported in a second study where participants' accountability to the pro‐fox hunters was removed, leaving them solely accountable to the experimenters, and similar results were obtained. In the final study, the relationship between student participants and staff experimenters was made the explicit topic of study. As expected students increased their endorsement of activities that are normative to students but unacceptable to staff when visible to fellow in‐group members. Together these results provide further support for the SIDE model.

This chapter challenges traditional models of deindividuation. These are based on the assumption that such factors as immersion in a group and anonymity lead to a loss of selfhood and hence of control over behaviour. We argue that such models depend upon an individualistic conception of the self, viewed as a unitary construct referring to that which makes individuals unique. This is rejected in favour of the idea that self can be defined at various different levels including the categorical self as well as the personal self. Hence a social identity model of deindividuation (SIDE) is outlined. Evidence is presented to show that deindividuation manipulations gain effect, firstly, through the ways in which they affect the salience of social identity (and hence conformity to categorical norms) and, secondly, through their effects upon strategic considerations relating to the expression of social identities. We conclude that the classic deindividuation paradigm of anonymity within a social group, far from leading to uncontrolled behaviour, maximizes the opportunity of group members to give full voice to their collective identities.