TBX3, a member of the ancient and evolutionary conserved T-box transcription factor family, is a critical developmental regulator of several structures including the heart, mammary glands, limbs and lungs. Indeed, mutations in the human TBX3 lead to ulnar mammary syndrome which is characterized by several clinical malformations including hypoplasia of the mammary and apocrine glands, defects of the upper limb, areola, dental structures, heart and genitalia. In contrast, TBX3 has no known function in adult tissues but is frequently overexpressed in a wide range of epithelial and mesenchymal derived cancers. This overexpression greatly impacts several hallmarks of cancer including bypass of senescence, apoptosis and anoikis, promotion of proliferation, tumour formation, angiogenesis, invasion and metastatic capabilities as well as cancer stem cell expansion. The debilitating consequences of having too little or too much TBX3 suggest that its expression levels need to be tightly regulated. While we have a reasonable understanding of the mutations that result in low levels of functional TBX3 during development, very little is known about the factors responsible for the overexpression of TBX3 in cancer. Furthermore, given the plethora of oncogenic processes that TBX3 impacts, it must be regulating several target genes but to date only a few have been identified and characterised. Interestingly, while there is compelling evidence to support oncogenic roles for TBX3, a few studies have indicated that it may also have tumour suppressor functions in certain contexts. Together, the diverse functional elasticity of TBX3 in development and cancer is thought to involve, in part, the protein partners that it interacts with and this area of research has recently received some attention. This review provides an insight into the significance of TBX3 in development and cancer and identifies research gaps that need to be explored to shed more light on this transcription factor.

Summary 1.In many animal populations a small proportion of individuals produce the majority of surviving offspring, but the underlying mechanisms are unclear. Behaviour may be an important determinant of variation in fitness: 'high-quality' individuals may have enhanced abilities in foraging or predator and parasite avoidance. 2. The role of behaviour in determining variation in quality was examined using the common guillemot Uria aalge, a monogamous seabird with biparental care. Using a novel mixed model approach, we analysed binary data on breeding success of each pair attempting to breed in each year with variables critical to breeding success (timing of breeding; inferred age; breeding experience and success; number of nest sites and partners) as fixed effects. Random effects for year, male, female and each distinct pairing of a male and a female were included in the model, allowing a quality estimate to be derived for each individual and pair. A range of behaviours associated with breeding were examined in relation to these quality estimates. 3. Breeding success declined with timing of breeding, and increased initially with age before declining in old age. It increased with previous successful experience, not breeding experience per se, until senescence effects became apparent. For males, breeding success declined with increasing numbers of mates. 4. The most important behavioural determinants of quality operated at the level of the pair, with the time mates spent together at the site and chick feeding rates both positively related to quality. At the individual level, trip durations and feeding rates were associated with female but not male quality, suggesting that pair quality was operating principally through the female. However, removal of laying date, the most important component in the binomial model, confirmed that the pair effect was much larger than the female effect. 5. This study demonstrates the potential of mixed modelling to determine quality estimates based on long-term breeding histories. The probability of a successful reproductive attempt was explained by the timing of breeding, age, successful breeding experience and number of mates. Behaviour was an important proximate mechanism underlying quality, in particular the foraging abilities of the pair, and the female's contribution to offspring provisioning. In species with biparental care, behavioural correlates of quality operate most strongly at the scale of the breeding pair, because contributions from both individuals are required for a successful outcome.

During the 1990s and early 2000s, populations of surface-nesting seabirds at Marion Island showed different trends, but for the majority of species numbers decreased. Reduced numbers of gentoo penguins Pygoscelis papua, eastern rockhopper penguins Eudyptes chrysocome filholi, Crozet shags Phalacrocorax [atriceps] melanogenis and probably macaroni penguins E. chrysolophus are most plausibly attributed to an altered availability of food. Decreases in numbers of dark-mantled sooty albatrosses Phoebetria fusca, light-mantled sooty albatrosses P. palpebrata, southern giant petrels Macronectes giganteus and possibly northern giant petrels M. halli may have resulted from mortality of birds in longline fisheries. However, populations of wandering Diomedea exulans and grey-headed Thalassarche chrysostoma albatrosses fluctuated around a stable level. Numbers of Subantarctic skuas Catharacta antarctica and kelp gulls Larus dominicanus breeding at Marion Island also decreased. Kerguelen Sterna virgata and Antarctic S. vittata terns remain scarce at the island. Trends for king penguins Aptenodytes patagonicus were not reliably gauged, but numbers probably remained stable or increased. There were large fluctuations in numbers of king penguin chicks surviving to the end of winter.

The numbers of gentoo penguins Pygoscelis papua breeding at subantarctic Marion Island fell by 40% from 1994/95 to 2002/03, from 1 352 pairs to 806 pairs. Apart from a slight increase in 1998/99, there was a steady decrease in numbers breeding between 1995/96 and 2000/01, when the population stabilized. There is indication that in some years not all breeders nested and that some birds relocated to another colony after disturbance. From first clutches, pairs on average fledged between 0.01 chicks in 1997/98 and 0.58 chicks in 2002/03 (mean 0.38 ± 0.21). In 1994/95, replacement clutches increased the overall production of fledged chicks by 11%. Based on demographic parameters measured at other localities, the production of chicks at Marion Island was inadequate to maintain the population during the period 1995/96 -2000/01. Consistency in trends in breeding success at five colonies suggests that factors operating at a mesoscale, rather than those specific to particular colonies, often influenced breeding success. Laying was later than normal in 1997/98, when there was almost total breeding failure with large losses of eggs and small chicks to returning Subantarctic skuas Catharacta antarctica. Future research on this Near Threatened species at Marion Island must take full account of its susceptibility to human disturbance.