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Biomedical subjects

M Breen

Publications and source records attributed to M Breen.

81 records · Page 5Linked to original sources

FISH mapping and identification of canine chromosomes.

The karyotype of the domestic dog (Canis familiaris) is widely accepted as one of the most difficult mammalian karyotypes to work with. The dog has a total of 78 chromosomes; all 76 autosomes are acrocentric in morphology and show only a gradual decrease in length. Standardization of the canine karyotype has been performed in two stages. The first stage dealt only with chromosomes 1-21 which can be readily identified by conventional G-banding techniques. The remaining 17 autosomal pairs have proven to be very difficult to reliably identify by banding alone. To facilitate the identification of all canine chromosomes, chromosome-specific paint probes have been produced by DOP-PCR from flow-sorted dog chromosomes. Each paint probe has been used for FISH to identify the corresponding chromosome(s), allowing precise identification of all 78 canine chromosomes. The identification of the undesignated 17 autosomal pairs has been agreed upon by the standardization committee during the second stage of their role. Cosmid clones containing microsatellite markers may now be conclusively assigned to their chromosomal origin by simultaneous dual-color FISH with the corresponding paint probe. In this way a collection of chromosome-specific cosmid clones is being constructed, comprising at least one marker per chromosome, which will allow anchoring of existing and future linkage groups to the physical map.

Animals↗

Use of cosmid-derived and chromosome-specific canine microsatellites.

The majority of microsatellite markers being used to generate the emerging genetic linkage maps of the dog are derived from small-insert, random clones. While such markers are easy to generate, they have the disadvantage that they cannot easily be physically mapped by fluorescence in situ hybridization (FISH), making it difficult to assess the extent of genome coverage represented by such maps. In contrast, microsatellite markers from large-insert libraries enable the linkage groups within which they fall to be physically anchored to specific chromosomes. One aim of our work is to identify at least one microsatellite-containing cosmid clone for each canine chromosome, to ensure that linkage groups exist for all chromosomes. This is particularly important for a species with as complex a karyotype as the dog. Locating two cosmids on each chromosome would allow the orientation of the linkage groups to be established. Chromosomal locations of cosmid clones containing microsatellites have been determined by FISH and confirmed using canine chromosome-specific paints. Microsatellite sequences have been genotyped on the DogMap reference family. Microsatellites derived from flow-sorted, chromosome-specific libraries represent another source of useful markers. Initial studies have been carried out on the canine X chromosome, on which markers were underrepresented in our initial studies.

Animals↗

Confronting adolescent bias and intolerance through cross-cultural immersion: an American-Croatian collaboration.

This article describes a partnership to develop youth leaders and positive interventions to reverse the cycles of violence and bigotry that come when young people experience the pain and trauma of growing up in a war zone. In Croatia, Project REACH (Recreational and Educational Activities for Children's Health) serves youth who have lost their families--and their innocence--in the senseless war and "ethnic cleansing" of the former Yugoslavia. Its partner, The Children's Village (CV), provides residential treatment services for youth who have lost their families as a result of chronic abuse or neglect and who have been exposed to high levels of family and community violence in one of the most beleaguered urban areas in the United States. The partnership exposed young people from these two supposedly different parts of the world to experiences that would enable them to examine their lives, their biases, and their assumptions about the world. It was hoped that participating youth would come to see their own potential to be leaders in breaking a cycle of violence, promoting tolerance and understanding, and creating a positive effect on the world around them.

Adolescent↗