Subject(s)
Mice, Inbred Strains/genetics , Animals , Female , Karyotyping , Male , Mice , Species SpecificitySubject(s)
Meiosis , Mice , Sex Chromosomes , Animals , Animals, Laboratory , Female , Male , Species SpecificityABSTRACT
Minced seminiferous tubules of male Chinese hamsters when treated with a mixture of trypsin (one part) and McCoy's 5a growth medium with 20% fetal calf serum (nine parts) at 4 degrees C, washed twice with the regular growth medium, incubated at 37 degrees C in growth medium for 4 h, and harvested without Colcemid and hypotonic pretreatments, gave excellent pachytene morphology for studies on chromomere patterns. The Giemsa banding patterns of all somatic metaphase chromosomes except the sex chromosomes of the hamster cells correspond well to the chromomere patterns of meiotic pachytene bivalents.
Subject(s)
Chromosome Mapping , Cricetinae , Meiosis , Spermatocytes/ultrastructure , Spermatozoa/ultrastructure , Animals , Cells, Cultured , Male , Mitosis , Seminiferous Tubules , Sex Chromosomes , TrypsinABSTRACT
The DNA replication patterns of the terminal S phase of three species of Mus were analyzed by tritiated thymidine autoradiography. The centromeric heterochromatin of M. fulvidiventris is the latest component to finish DNA synthesis. The Y chromosome finishes replication earlier than the centromeric heterochromatin. The centromeric heterochromatin of M. musculus, on the other hand, is not the latest component to finish DNA synthesis. At the very late S phase, grains are found in the euchromatic arms instead of the heterochromatic areas. The "hot X" and the "hot Y" can be identified in the majority of, but not all, cases. The heterochromatic short arms of the autosomes in M. dunni finish DNA replication earlier than many areas in the euchromatic long arms and the heterochromatin of the sex chromosomes. This indicates that in M. dunni there are at least two types of heterochromatin. The late-replicating zones in the euchromatic long arms are distinctly banded. This banded grain pattern can be seen in all Mus species observed, but in M. dunni it is most exaggerated. Late-replicating chromosome segments can be demonstrated also by 2+ cycles of BUdR incorporation and Giemsa staining.
Subject(s)
Chromosomes , DNA , Mice/anatomy & histology , Animals , Autoradiography , Cells, Cultured , DNA Replication , Heterochromatin , Sex Chromosomes , Species Specificity , Thymidine , Time Factors , TritiumSubject(s)
Benzimidazoles , Chromosomes/ultrastructure , Animals , Cattle , Methods , Mice , Microscopy, Fluorescence , Staining and Labeling , Time FactorsABSTRACT
The chromosomes of the Asian mice, Mus fulvidiventris (booduga?), are typical of the Mus in general, viz., 40 telocentric chromosomes. The centromeric heterochromatin does not fluoresce brightly. The G band pattern of the euchromatin is the same as that of M. musculus. The diploid number of M. dunni is also 40, but each autosome possesses a short, heterochromatic second arm. The X chromosome is a long submetacentric, whose entire short arm and the terminal segment of the long arm are heterochromatic. The Y is a long telocentric and is heterochromatic. The G band pattern of the long arms of M. dunni involved only the addition of C bands. Mus dunni and M. booduga are sympatric in many localities in India, but they can be separated by karyological and subtle morphological differences.
