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A mouse-human somatic cell hybrid clone, deficient in hypoxanthine-guanine phosphoribosyltransferase (HPRT) and containing a structurally normal inactive human X chromosome, was isolated. The hybrid cells were treated with 5-azacytidine and tested for the reactivation and expression of human X-linked genes. The frequency of HPRT-positives clones after(More)
Human STS is a microsomal enzyme important in steroid metabolism. The gene encoding STS is pseudoautosomal in the mouse but not in humans, and escapes X inactivation in both species. We have prepared monoclonal and polyclonal antibodies to the protein which has been purified and from which partial amino acid sequence data have been obtained. cDNA clones(More)
One of the most distinctive aspects of primate quadrupedal walking is the use of diagonal sequence footfalls in combination with diagonal-couplets interlimb timing. Numerous hypotheses have been offered to explain why primates might have evolved this type of gait, yet this important question remains unresolved. Because infant primates use a wider variety of(More)
As predicted by Darwin, bipedal posture and locomotion are key distinguishing features of the earliest known hominins. Hominin axial skeletons show many derived adaptations for bipedalism, including an elongated lumbar region, both in the number of vertebrae and their lengths, as well as a marked posterior concavity of wedged lumbar vertebrae, known as a(More)
Substantial DNA deletions appear to be the molecular basis of several human genetic disorders but rarely account for the majority of observed mutations at any given locus. Exceptions in which deletions do account for the majority of observed abnormalities include the alpha-thalassemias, Duchenne muscular dystrophy, and steroid sulfatase deficiency. Variable(More)
Locomotor features shared by arboreal marsupials and primates are frequently cited as a functional complex that evolved in the context of a "fine branch niche." Adaptation to a fine branch niche cannot be understood without considering that small and large arboreal mammals may differ in their biomechanical response to a given branch size. We tested the(More)
Mammalian sex chromosomes are divided into sex-specific and pseudoautosomal regions. Sequences in the pseudoautosomal region recombine between the sex chromosomes; the sex-specific sequences normally do not. The interface between sex-specific and pseudoautosomal sequences is the pseudoautosomal boundary. The boundary is the centromeric limit to(More)
Recently proposed ancestral locomotor and morphological 'stages' leading to the evolution of primates have emphasized small body size, and a transition from a clawed non-grasping stage, to a clawed, grasping stage with clawless opposable hallux, to a fully-nailed primate with grasping extremities. This evolutionary transition was presumably associated with(More)
Taillessness is a distinctive synapomorphy of the Hominoidea that has implications for interpretation of the locomotor behaviors and phylogenetic affinities of the clade's earliest members. However, difficulties persist in confidently identifying taillessness in the catarrhine fossil record, stemming largely from our limited knowledge of the anatomical(More)