This thesis focuses on important life history traits and their trade-offs using two hexapod models. Particularly, the trade-off between immune defense and embryonic developmental speed is a central... Show moreThis thesis focuses on important life history traits and their trade-offs using two hexapod models. Particularly, the trade-off between immune defense and embryonic developmental speed is a central theme of this study. In short, I study the details of immune defenses during embryonic development of basal hexapods in Chapter 2, the trade-off with developmental speed in Chapter 3, and the genetic basis of developmental speed in Chapter 4, using selection lines of the red flour beetle Tribolium castaneum. I demonstrate that 1) springtail eggs do show an immune response, despite absence of a serosa that provides immune protection to insect eggs; 2) a strong trade-off is present between developmental speed and fecundity in the selection lines of the beetle T. castaneum; and 3) a life-history allele of large effect shortens developmental time in this wild insect population. I suggest that such alleles of large effect play a crucial role when insects have to adapt their developmental speed to current climate change. Show less
Genetic factors play an important role in the regulation of human life span but the exact pathways remain to be elucidated, however they may be interrelated with the regulation of human... Show moreGenetic factors play an important role in the regulation of human life span but the exact pathways remain to be elucidated, however they may be interrelated with the regulation of human reproduction. It is argued that an innate cytokine profile supportive of Th1-type T cells favors survival of infectious diseases (with longevity as the ultimate), but women with this profile are found less likely to have successful pregnancies (progeny). The probability of a normal fertility was found to increase more than 10-fold when the innate cytokine profile was characterized by high IL-10 (Th-2 cytokine) and low TNF- (Th-1 cytokine) responsiveness. The IL10 –2849 AA genotype was found to be associated with a decreased fertility and fecundity (time to pregnancy) in females, possibly due to the lower expected IL10 responsiveness. Rheumatoid arthritis (RA) is an example of a Th-1 mediated disease. It was found that the phenotype of joint destruction in RA was associated with the phenotype of reported miscarriages, suggesting common genetic risk factors for each of these two traits, possibly through the innate Th-1/Th-2 phenotype. Factor V Leiden (FVL) is a point mutation in the factor V gene generating a 7-fold increase in incidence of deep vein thrombosis. Specific advantages of the FVL mutation in early pregnancy (implantation) might balance its potentially harmful effects later in life and explain the remarkably high prevalence of this mutation in the general population. Show less
