摘要:

Restriction analysis had revealed onlyMus domesticusmtDNA in house mouse populations in northern Denmark, Sweden, and Finland, where the nuclear genomes areMus musculus.The goals of the present study were to (1) test the proposal that these Scandinavianmusculusmice arose by a series of founder and island‐hopping events from one or a few populations near thedomesticus‐musculushybrid zone on the East Holstein Peninsula of northern Germany and (2) see whether more than the two types ofdomesticusmtDNA detected by restriction analysis existed among thesemusculuspopulations. Sequences of the 1 ‐kilobase mtDNA segment encompassing the entire control region and the flanking tRNAs were gathered from 217domesticusandmusculusmice. Included were 104‐mice from 12 localities across a 120‐km transect of the Holstein hybrid and adjacent zones, 56 animals from 12 localities in themusculusrange of Scandinavia, 56domesticusmice representing 46 localities in Europe, North Africa, the Middle East, and the Americas, and onemusculusmouse from Czechoslovakia. Save for the Czech mouse, all individuals haddomesticusmtDNA, a total of 56 types being resolved and 10 of these being found among the Holstein mice. Electrophoresis of proteins encoded by nuclear loci along with assessment of external morphology and of skeletal, cranial, and dental traits revealed a transition fromdomesticustomusculusnuclear genomes over a distance of about 20–40 km in East Holstein. Of the 216 mtDNAs, 149 fall into a clade of 17 types characterized by the addition of an 11‐bp direct repeat; included are all Swedish, Finnish, and northern Danish mtDNAs as well as 82 from the Holstein transect. Support for the previously proposed migration pathway from the European mainland to Scandinavia came from finding that on thedomesticusside of the hybrid zone in Holstein a high proportion of mice carry the types of mtDNA found in the mice withmusculusnuclear genomes. Sequencing revealed 11 different mtDNAs in the +11‐bp clade amongmusculusmice, one of these being widespread, seven others being confinedtosingle localities, and one Danish collecting locality yielding five types. The mitochondrial diversity uncovered among these mice leads to a reexamination of some aspects of the original model, notably with respect to the number of founding females, the possible role of selection, and the possibility of an accelerated rate of mtDNA evolution. This study also showed that for the mouse control region the transition/ transversion ratio is significantly lower than for the human control region and that small length mutations occur about as frequently as transversions during mouse control region evolution.SUMMARYControl region and flanking tRNA sequences were obtained from 21 7 European commensal house mice, especially Scandinavian and East HolsteinMus musculusthat carry onlyMus domesticusmtDNA. Among the 56 types ofdomesticusmtDNA identified, 17 types, collectively representing 149 mice, have an added 1 1‐bp repeat; 11 types in the + 1 1‐bp clade were found amongmusculusmice. Finding + 11‐bp mtDNAs also in many East Holsteindomesticusmice supports the model that the Scandinavianmusculusmice arose by a series of island‐hopping events from near thedomesticus‐musculushybrid zone on the East Holstein Peninsula of northern Germany, while the mtDNA diversity detected encourages reexamination of ideas about the number of founding females and the role of selection. The nuclear and cytological genotypes of 104 animals collected from 12 localities along a 120‐km transect through the East Holstein hybrid zone were characterized by electrophoresis of proteins at three diagnostic loci, assessment of several morphological traits, and karyotyping. These studies reveal a transition fromdomesticustomusculusnuclear genomes over about 20–40 km, differential penetration ofdomesticusalleles intomusculusterritory, and no Robertsonian translocations. The number of tail vertebrae provided a new assessment of species differences, with more vertebrae identified as the osteological basis for the longer tails c

ISSN:0024-4066    

DOI:10.1111/j.1095-8312.1993.tb00920.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY

摘要:

If animals mature at small sizes and then grow to larger asymptotic sizes, many factors can affect male and female size distributions. Standard growth equations can be used to study the processes affecting sexual size dimorphism in species with asymptotic growth after maturity. This paper first outlines the effects of sex differences in growth and maturation patterns on the direction and degree of sexual dimorphism. The next section considers the effects of variation in age structure or growth rates on adult body sizes and sexual size dimorphism. Field data from a crustacean, fish, lizard and mammal show how information on a species' growth and maturation patterns can be used to predict the relationships between male size, female size and sexual size dimorphism expected if a series of samples from the same population simply differed with respect to their ages or growth rates. The last section considers ecological or behavioural factors with different effects on the growth, maturation, survival or movement patterns of the two sexes. This study supports earlier suggestions that information on growth and maturation patterns may be useful, if not essential, for comparative studies of sexual size dimorphism in taxa with asymptotic growth after maturity.

ISSN:0024-4066    

DOI:10.1111/j.1095-8312.1993.tb00921.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY

摘要:

The hindlimb (myology and osteology) of swallows (Hirundinidae) is studied and compared with that of seven other passerine families to identify ecomorphological patterns. Muscular and osteological differences are found among swallow species and associations between morphology and foraging technique are examined. We explain morphological differences found in hirundinids as adaptations favouring flexion and adduction of the legs in these aerial foragers, which devote very little time to cursorial locomotion. This adaptive hypothesis is tested using a phylogenetic approach on the basis of an available molecular phylogenetic hypothesis. A clear ecomorphological pattern emerges relating foraging behaviour and pelvic morphology in hirundinids: aerial feeding technique is correlated with short distal leg segments, a large pelvis, a medial insertion of M. iliotibialis cranialis, an absence of pars accessoria of M. flexor cruris lateralis and a fused M. pubo‐ischiofemorali

ISSN:0024-4066    

DOI:10.1111/j.1095-8312.1993.tb00922.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY