Biomaterial Database

Meiosis and fertility in common shrews, Sorex araneus, from a chromosomal hybrid zone in central Sweden. 1997

Y Narain, and K Fredga

Department of Genetics, Uppsala University, Sweden.

Adult male common shrews from the Uppsala and Hällefors Robertsonian chromosomal races and hybrids were collected from the area of Surahammar in Sweden. Meiosis and fertility of hybrid (complex heterozygotes) and nonhybrid (homozygotes) individuals were compared based on an analysis of chromosomal interactions and synapsis at pachytene, chiasma characteristics at diakinesis, and germ-cell death. No individuals suffered severe germ-cell loss, and the differences found among the Uppsala and Hällefors homozygotes and the hybrids were not significant. In complex heterozygotes, ring configurations of four elements were observed at meiosis I, with one chiasma per chromosome arm. Abnormal rings were frequent at pachytene, but interactions between the ring and other chromosomes were seldom found. There is no indication from this study of a differential fertility between homozygotes and ring IV-forming complex heterozygotes in males.

UI	MeSH Term	Description	Entries
D008297	Male		Males
D008540	Meiosis	A type of CELL NUCLEUS division, occurring during maturation of the GERM CELLS. Two successive cell nucleus divisions following a single chromosome duplication (S PHASE) result in daughter cells with half the number of CHROMOSOMES as the parent cells.	M Phase, Meiotic,Meiotic M Phase,M Phases, Meiotic,Meioses,Meiotic M Phases,Phase, Meiotic M,Phases, Meiotic M
D008854	Microscopy, Electron	Microscopy using an electron beam, instead of light, to visualize the sample, thereby allowing much greater magnification. The interactions of ELECTRONS with specimens are used to provide information about the fine structure of that specimen. In TRANSMISSION ELECTRON MICROSCOPY the reactions of the electrons that are transmitted through the specimen are imaged. In SCANNING ELECTRON MICROSCOPY an electron beam falls at a non-normal angle on the specimen and the image is derived from the reactions occurring above the plane of the specimen.	Electron Microscopy
D002875	Chromosomes	In a prokaryotic cell or in the nucleus of a eukaryotic cell, a structure consisting of or containing DNA which carries the genetic information essential to the cell. (From Singleton & Sainsbury, Dictionary of Microbiology and Molecular Biology, 2d ed)	Chromosome
D005298	Fertility	The capacity to conceive or to induce conception. It may refer to either the male or female.	Fecundity,Below Replacement Fertility,Differential Fertility,Fecundability,Fertility Determinants,Fertility Incentives,Fertility Preferences,Fertility, Below Replacement,Marital Fertility,Natural Fertility,Subfecundity,World Fertility Survey,Determinant, Fertility,Determinants, Fertility,Fertility Determinant,Fertility Incentive,Fertility Preference,Fertility Survey, World,Fertility Surveys, World,Fertility, Differential,Fertility, Marital,Fertility, Natural,Preference, Fertility,Preferences, Fertility,Survey, World Fertility,Surveys, World Fertility,World Fertility Surveys
D006579	Heterozygote	An individual having different alleles at one or more loci regarding a specific character.	Carriers, Genetic,Genetic Carriers,Carrier, Genetic,Genetic Carrier,Heterozygotes
D006720	Homozygote	An individual in which both alleles at a given locus are identical.	Homozygotes
D006824	Hybridization, Genetic	The genetic process of crossbreeding between genetically dissimilar parents to produce a hybrid.	Crossbreeding,Hybridization, Intraspecies,Crossbreedings,Genetic Hybridization,Genetic Hybridizations,Hybridizations, Genetic,Hybridizations, Intraspecies,Intraspecies Hybridization,Intraspecies Hybridizations
D000818	Animals	Unicellular or multicellular, heterotrophic organisms, that have sensation and the power of voluntary movement. Under the older five kingdom paradigm, Animalia was one of the kingdoms. Under the modern three domain model, Animalia represents one of the many groups in the domain EUKARYOTA.	Animal,Metazoa,Animalia
D012788	Shrews	Small mammals in the family Soricidae, order Soricomorpha (formerly Insectivora). They resemble moles and are characterized by a mobile snout, sharp INCISOR teeth, and are found in tropical and temperate regions worldwide.	Shrew