There is increasing evidence that HOX homeobox genes play a role in leukemogenesis. Recent studies have demonstrated that enforced co-expression of HOXA9 and MEIS1 in murine marrow leads to rapid development of myeloid leukemia, and that these proteins exhibit cooperative DNA binding. However, it is unclear whether co-activation of HOXA9 and MEIS genes is a common occurrence in human leukemias. We surveyed expression of HOXA9 and MEIS1 in 24 leukemic cell lines and 80 patient samples, using RNase protection analyses and immunohistochemistry. We demonstrate that the expression of HOXA9 and MEIS1 in leukemia cells is uniquely myeloid, and that these genes are commonly co-expressed in myeloid cell lines and in samples of acute myelogenous leukemia (AML) of all subtypes except in promyelocytic leukemia. While HOXA9 is expressed in most cases of chronic myelogenous leukemia, MEIS1 is weakly expressed or not at all. Immunohistochemical staining of selected AML samples showed moderate to high levels of HOXA9 protein, primarily cytoplasmic, in leukemic myeloblasts, with weaker and primarily nuclear staining for MEIS1. These data support the concept that co-activation of HOXA9 and MEIS1 is a common event in AML, and may represent a common pathway of many different oncogenic mutations.

The extinction of large northern herbivores is a puzzle for many biologists. Is it caused by climate change or human activity? The survival of the weak trophic competitors promotes the “anthropogenic” hypothesis. The extant species of Pleistocene communities allow us to easily test this assumption. The reindeer and musk ox have been until now coexisting in the Arctic territory. Their island populations form a unique natural experiment for assessing the role of competition. On Wrangel Island, changes in their abundance occur with the opposite trends. The same situation recurs on other Arctic islands. The reindeer population decreases, while the musk oxen population becomes larger. We have found that the above trends are determined by the food web structure. The niche overlap between species is considerable and cannot be facilitated by habitat partitioning. The number of plant species in the musk oxen diet is higher than in the reindeer. The exclusive part of the musk ox diet was higher as well. The reindeer occupies a worse position in all of the habitat types. However, the changes in herbivores distribution during the Pleistocene demonstrate opposite results. Therefore, the competitive advantage could not save the Palaearctic musk ox, and its extinction seems to be the result of selective overkill. Conclusively, human activity may be considered as the main factor of the Late Pleistocene herbivore extinctions, and reintroduction of the musk ox should be coupled with extensive conservation.

In the 20th century, the breeding grounds of the barnacle goose over the territory of Russia included only the Novaya Zemlya Archipelago and Vaygach Island. Until the middle of the century, the population did not exceed 20 000–30 000 individuals. In the 1970s–1980s, the population of the barnacle goose started increasing slowly. Shortly thereafter new colonies appeared in the coastal areas of the Barents Sea, ranging from the Kanin Peninsula to Khaypudyrskaya Bay and Kolguev Island. By 2017, the population numbers had reached about 1.2 million individuals. The increase in the barnacle goose population has coincided with the phase of a pronounced temperature increase and general climate change in the Arctic. The mean annual temperatures have increased significantly in the Eastern European tundra. A simultaneous ice cover decline in the Barents Sea has led to spreading of the warm Atlantic waters much further to the east and thus rendering a heating effect extending as far as the Kara Sea. One of the consequences is a steady decrease in weather differences between the western and eastern parts of the region. The climate in the eastern part, in Vaygach Island and the Yugor Peninsula in particular, has become milder and changes relatively faster than in the western part of the region. This is believed to be one of the reasons for the vast expansion of the barnacle goose to the east and to Kolguev Island. In the spring period, in May and June, the average daily temperatures in the Eastern European tundra have not changed significantly over the past 35 years, but taking into account the lack of a pronounced temperature increase, the transition of the mean daily temperature over 0°C has shifted to a much earlier period. On the territory of the Eastern European tundra, the cumulative temperature of the summer period has increased along with the duration of the period with positive temperatures. These factors combined have led to a prolonged vegetation period and have enhanced phytomass growth. This trend is most pronounced in the post-hatching period, i.e., in July and August. The prolongation of the active vegetation period offers young barnacle geese additional advantages in one of the most crucial periods of their life, i.e., the fledging period. Adult birds have an additional opportunity to accumulate internal reserves before the autumn migration. Apparently, all these factors combined seem to have allowed for new habitats on marshes and in the typical plain tundra to be used by barnacle geese, leading to a significant increase in the numbers of the species. More detailed information obtained now fails to support the hypothesis stipulating the adverse impact of a phenological mismatch on the barnacle goose. The species continues demonstrating steady population growth. According to our estimations, there are 1 069 107 ± 37 655 barnacle geese in the Russian part of its range (excluding the Novaya Zemlya Archipelago).

In Russia, the conservation of anseriformes is possible through the creation of temporary huntingfree zones during hunting season, especially in spring. A justification for creating such zones and...