Biomedical subjects

Ofer Peleg

Publications and source records attributed to Ofer Peleg.

5 recordsLinked to original sources

PubMed2006

Hereditary family signature of facial expression.

Although facial expressions of emotion are universal, individual differences create a facial expression "signature" for each person; but, is there a unique family facial expression signature? Only a few family studies on the heredity of facial expressions have been performed, none of which compared the gestalt of movements in various emotional states; they compared only a few movements in one or two emotional states. No studies, to our knowledge, have compared movements of congenitally blind subjects with their relatives to our knowledge. Using two types of analyses, we show a correlation between movements of congenitally blind subjects with those of their relatives in think-concentrate, sadness, anger, disgust, joy, and surprise and provide evidence for a unique family facial expression signature. In the analysis "in-out family test," a particular movement was compared each time across subjects. Results show that the frequency of occurrence of a movement of a congenitally blind subject in his family is significantly higher than that outside of his family in think-concentrate, sadness, and anger. In the analysis "the classification test," in which congenitally blind subjects were classified to their families according to the gestalt of movements, results show 80% correct classification over the entire interview and 75% in anger. Analysis of the movements' frequencies in anger revealed a correlation between the movements' frequencies of congenitally blind individuals and those of their relatives. This study anticipates discovering genes that influence facial expressions, understanding their evolutionary significance, and elucidating repair mechanisms for syndromes lacking facial expression, such as autism.

Blindness↗

PubMed2004

Overlapping messages and survivability.

The phenomenon of overlapping of various sequence messages in genomes is a puzzle for evolutionary theoreticians, geneticists, and sequence researchers. The overlapping is possible due to degeneracy of the messages, in particular, degeneracy of codons. It is often observed in organisms with a limited size of genome, possessing polymerases of low fidelity. The most accepted view considers the overlapping as a mechanism to increase the amount of information per unit length. Here we present a model that suggests direct evolutionary advantage of the message overlapping. Two opposing drives are considered: (a) reduction in the amount of vulnerable points when the overlapping of two messages involves common critical points and (b) cumulative compromising cost of coexistence of messages at the same site. Over a broad range of conditions the reduction of the target size prevails, thus making the overlapping of messages advantageous.

Animals↗

PubMed2004

Large retrotransposon derivatives: abundant, conserved but nonautonomous retroelements of barley and related genomes.

Retroviruses and LTR retrotransposons comprise two long-terminal repeats (LTRs) bounding a central domain that encodes the products needed for reverse transcription, packaging, and integration into the genome. We describe a group of retrotransposons in 13 species and four genera of the grass tribe Triticeae, including barley, with long, approximately 4.4-kb LTRs formerly called Sukkula elements. The approximately 3.5-kb central domains include reverse transcriptase priming sites and are conserved in sequence but contain no open reading frames encoding typical retrotransposon proteins. However, they specify well-conserved RNA secondary structures. These features describe a novel group of elements, called LARDs or large retrotransposon derivatives (LARDs). These appear to be members of the gypsy class of LTR retrotransposons. Although apparently nonautonomous, LARDs appear to be transcribed and can be recombinationally mapped due to the polymorphism of their insertion sites. They are dispersed throughout the genome in an estimated 1.3 x 10(3) full-length copies and 1.16 x 10(4) solo LTRs, indicating frequent recombinational loss of internal domains as demonstrated also for the BARE-1 barley retrotransposon.

3' Untranslated Regions↗

PubMed2003

Hidden messages in the nef gene of human immunodeficiency virus type 1 suggest a novel RNA secondary structure.

The coexistence of multiple codes in the genome of human immunodeficiency virus type 1 (HIV-1) was analyzed. We explored factors constraining the variability of the virus genome primarily in relation to conserved RNA secondary structures overlapping coding sequences, and used a simple combination of algorithms for RNA secondary structure prediction based on the nearest-neighbor thermodynamic rules and a statistical approach. In our previous study, we applied this combination to a non- redundant data set of env nucleotide sequences, confirmed the conservative secondary structure of the rev-responsive element (RRE) and found a new RNA structure in the first conserved (C1) region of the env gene. In this study, we analyzed the variability of putative RNA secondary structures inside the nef gene of HIV-1 by applying these algorithms to a non-redundant data set of 104 nef sequences retrieved from the Los Alamos HIV database, and predicted the existence of a novel functional RNA secondary structure in the beta3/beta4 regions of nef. The predicted RNA fold in the beta3/beta4 region of nef appears in two forms with different loop sizes. The loop of the first fold consists of seven nucleotides (positions 494-500), with consensus UCAAGCU appearing in 79% of sequences. The other has a five-base loop (positions 495-499) with consensus CAAGC. The difference in size between these two loops may reflect the difference between respective counterparts in the hairpin recognition. This may also have an adaptive biological significance.

Algorithms↗

PubMed2002

RNA secondary structure and squence conservation in C1 region of human immunodeficiency virus type 1 env gene.

We have analyzed amino acid, nucleotide sequence, and RNA secondary structure variability in the env gene of human immunodeficiency virus type (HIV-1). In applying algorithms for computing optimal RNA-folding patterns to a nonredundant data set of 178 env nucleotide sequences, we found a conserved RNA stem-loop structure in the first conserved (C1) region of the env gene. This detailed examination also revealed the known secondary structure conservation of the Rev-responsive element (RRE). This finding is also supported by a higher third position conservation of the translatable reading frame along these subregions. The typical folding of the C1 region consists of two isolated stem-loop structures. These highly conserved structures are likely to have a biological function. This assumption is supported by the conservation of the third position along the coding region of these structures. The third position retains a conservation level above what would be statistically expected.

Algorithms↗