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311.
Hildegard Leistner 《Cell and tissue research》1936,25(1):34-65
Ohne Zusammenfassung 相似文献
312.
313.
Dr. Hildegard Vollmar 《Cell and tissue research》1936,23(3):571-572
Ohne Zusammenfassung 相似文献
314.
315.
Hildegard Juhl-Noodt 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1955,25(3):80-86
Ohne ZusammenfassungMit 13 Textabbildungen. 相似文献
316.
Hildegard Uecker 《Evolution; international journal of organic evolution》2017,71(4):845-858
Severe environmental change can drive a population extinct unless the population adapts in time to the new conditions (“evolutionary rescue”). How does biparental sexual reproduction influence the chances of population persistence compared to clonal reproduction or selfing? In this article, we set up a one‐locus two‐allele model for adaptation in diploid species, where rescue is contingent on the establishment of the mutant homozygote. Reproduction can occur by random mating, selfing, or clonally. Random mating generates and destroys the rescue mutant; selfing is efficient at generating it but at the same time depletes the heterozygote, which can lead to a low mutant frequency in the standing genetic variation. Due to these (and other) antagonistic effects, we find a nontrivial dependence of population survival on the rate of sex/selfing, which is strongly influenced by the dominance coefficient of the mutation before and after the environmental change. Importantly, since mating with the wild‐type breaks the mutant homozygote up, a slow decay of the wild‐type population size can impede rescue in randomly mating populations. 相似文献
317.
The transition temperature of phosphatidylglycerol (PG) was reduced to lower temperatures in presence of propranolol, imipramine, amitriptyline and chlorpromazine. This effect was dependent on drug concentration and was smallest with propranolol. The fluidizing effect, however, increased from propranolol to chlorpromazine according to the octanol/H2O partition coefficients. When the two phospholipids PG and phosphatidylcholine (PC) were compared, the presence of drug lead to a more pronounced reduction of the transition temperature in the case of the acidic phospholipid than in the case of the neutral one. 相似文献
318.
319.
Longevity of a taxonomic group is an important issue in understanding the dynamics of evolution. In this respect a key observation
is that genera, families or orders can each be assigned a characteristic average lifetime (Van Valen in Evol Theory 1:1–30,
1973). Using the fossil marine animal genera database (Sepkoski in Bull Am Paleontol 363, pp 563, 2002) we here examine the relationship between longevity of a higher taxonomic group (orders) and the longevity of its lower taxonomic
groups (genera). We find insignificant correlation between the size of an order and its longevity, whereas we observe large
correlation between the lifetime of an order and the lifetime of its constituent genera. These observations suggest that longevity
of taxonomic groups is heritable intrinsically or on the grounds of environmental preferences. 相似文献
320.