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PubMed1993

[Interactions of infants with adults in day care centers. Evolutive dependencies vs. counter-evolutive risks and characteristics of the mother-infant relationship].

As part of a broader research project on the construction of the self, six infants were observed longitudinally in day-care centers between the ages of five months and three years. Interviews were conducted with the six mothers in order to evaluate the intersubjective characteristics of the mother-infant relationship. For three of the six children, the mother was a caregiver in the center. This article deals with "propping" processes, defined as the affective-cognitive transformations by means of which infants develop networks of links with and between external and internal objects which are used for support during development and serve as a relay of the maternal object. The present analysis is limited to propping on the adults in the day-care center (caregivers, observer, and, for three of the children, mothers). Two factors were considered: the intersubjective quality of the mother-infant relation, and the presence or absence of the mother as a caregiver in the day-care center. The results showed that (1) even when very young, the infants under observation differentiated between the various functions of the adults, and adapted their behavior to them; (2) each child exhibited a unique and sometimes very creative way of using dependencies on an adult's psychic apparatus to construct his or her own modes of psychic functioning; and (3) the developmental dynamics and the richness of the observed transformations were found to depend on the quality of the contact and distancing in the mother-infant relationship and on the concrete conditions for its actualization, which can either promote or hinder, and sometimes even block, the construction of the mother's absence.

Adult↗
PubMed2004

Adaptive evolution of HoxA-11 and HoxA-13 at the origin of the uterus in mammals.

The evolution of morphological characters is mediated by the evolution of developmental genes. Evolutionary changes can either affect cis-regulatory elements, leading to differences in their temporal and spatial regulation, or affect the coding region. Although there is ample evidence for the importance of cis-regulatory evolution, it has only recently been shown that transcription factors do not remain functionally equivalent during evolution. These results suggest that the evolution of transcription factors may play an active role in the evolution of development. To test this idea we investigated the molecular evolution of two genes essential for the development and function of the mammalian female reproductive organs, HoxA-11 and HoxA-13. We predicted that if coding-region evolution plays an active role in developmental evolution, then these genes should have experienced adaptive evolution at the origin of the mammalian female reproductive system. We report the sequences of HoxA-11 from basal mammalian and amniote taxa and analyse HoxA-11 and HoxA-13 for signatures of adaptive molecular evolution. The data demonstrate that these genes were under strong positive (directional) selection in the stem lineage of therian and eutherian mammals, coincident with the evolution of the uterus and vagina. These results support the idea that adaptive evolution of transcription factors can be an integral part in the evolution of novel structures.

Adaptation, Biological↗