| 1. |
- Lazaridis, Iosif, et al.
(författare)
-
Ancient human genomes suggest three ancestral populations for present-day Europeans
- 2014
-
Ingår i: Nature. - : Springer Science and Business Media LLC. - 0028-0836 .- 1476-4687. ; 513:7518, s. 409-
-
Tidskriftsartikel (refereegranskat)abstract
- We sequenced the genomes of a similar to 7,000-year-old farmer from Germany and eight similar to 8,000-year-old hunter-gatherers from Luxembourg and Sweden. We analysed these and other ancient genomes(1-4) with 2,345 contemporary humans to show that most present-day Europeans derive from at least three highly differentiated populations: west European hunter-gatherers, who contributed ancestry to all Europeans but not to Near Easterners; ancient north Eurasians related to Upper Palaeolithic Siberians(3), who contributed to both Europeans and Near Easterners; and early European farmers, who were mainly of Near Eastern origin but also harboured west European hunter-gatherer related ancestry. We model these populations' deep relationships and show that early European farmers had similar to 44% ancestry from a 'basal Eurasian' population that split before the diversification of other non-African lineages.
|
|
| 2. |
- Le Duc, Diana, et al.
(författare)
-
Kiwi genome provides insights into evolution of a nocturnal lifestyle
- 2015
-
Ingår i: Genome Biology. - : Springer Science and Business Media LLC. - 1465-6906 .- 1474-760X. ; 16
-
Tidskriftsartikel (refereegranskat)abstract
- Background: Kiwi, comprising five species from the genus Apteryx, are endangered, ground-dwelling bird species endemic to New Zealand. They are the smallest and only nocturnal representatives of the ratites. The timing of kiwi adaptation to a nocturnal niche and the genomic innovations, which shaped sensory systems and morphology to allow this adaptation, are not yet fully understood. Results: We sequenced and assembled the brown kiwi genome to 150-fold coverage and annotated the genome using kiwi transcript data and non-redundant protein information from multiple bird species. We identified evolutionary sequence changes that underlie adaptation to nocturnality and estimated the onset time of these adaptations. Several opsin genes involved in color vision are inactivated in the kiwi. We date this inactivation to the Oligocene epoch, likely after the arrival of the ancestor of modern kiwi in New Zealand. Genome comparisons between kiwi and representatives of ratites, Galloanserae, and Neoaves, including nocturnal and song birds, show diversification of kiwi's odorant receptors repertoire, which may reflect an increased reliance on olfaction rather than sight during foraging. Further, there is an enrichment of genes influencing mitochondrial function and energy expenditure among genes that are rapidly evolving specifically on the kiwi branch, which may also be linked to its nocturnal lifestyle. Conclusions: The genomic changes in kiwi vision and olfaction are consistent with changes that are hypothesized to occur during adaptation to nocturnal lifestyle in mammals. The kiwi genome provides a valuable genomic resource for future genome-wide comparative analyses to other extinct and extant diurnal ratites.
|
|
| 3. |
- Lizano, Esther, et al.
(författare)
-
A splice variant of the human CCA-adding enzyme with modified activity
- 2007
-
Ingår i: Journal of Molecular Biology. - : Elsevier BV. - 0022-2836 .- 1089-8638. ; 366:4, s. 1258-1265
-
Tidskriftsartikel (refereegranskat)abstract
- The human CCA-adding enzyme (tRNA nucleotidyltransferase) is an essential enzyme that catalyzes the addition of the CCA terminus to the 3′ end of tRNA precursors, a reaction which is a fundamental prerequisite for mature tRNAs to become aminoacylated and to participate in protein biosynthesis. To date only one form of this enzyme has been identified in humans. Here, we describe the sequence and activity of a splice variant of the human CCA-adding enzyme identified in public cDNA databases. The in silico analyses performed on this splice variant indicate that there is conservation of the alternative splice donor site among species and indicate that it seems to be used in vivo. Moreover, the recombinantly expressed protein is active in vitro and accepts tRNA transcripts as substrates incorporating the dinucleotide sequence CC to their 3′ end, in contrast to the activity of the full length enzyme. These findings strongly suggest that the splice variant of the human CCA-adding enzyme is expressed in the cell although the in vivo function remains unclear.
|
|
| 4. |
- Zeberg, Hugo, et al.
(författare)
-
A Neanderthal Sodium Channel Increases Pain Sensitivity in Present-Day Humans
- 2020
-
Ingår i: Current Biology. - : Elsevier. - 0960-9822 .- 1879-0445. ; 30:17, s. 3465-3469
-
Tidskriftsartikel (refereegranskat)abstract
- The sodium channel Nav1.7 is crucial for impulse generation and conduction in peripheral pain pathways [1]. In Neanderthals, the Nav1.7 protein carried three amino acid substitutions (M932L, V991L, and D1908G) relative to modern humans. We expressed Nav1.7 proteins carrying all combinations of these substitutions and studied their electrophysiological effects. Whereas the single amino acid substitutions do not affect the function of the ion channel, the full Neanderthal variant carrying all three substitutions, as well as the combination of V991L with D1908G, shows reduced inactivation, suggesting that peripheral nerves were more sensitive to painful stimuli in Neanderthals than in modern humans. We show that, due to gene flow from Neanderthals, the three Neanderthal substitutions are found in ∼0.4% of present-day Britons, where they are associated with heightened pain sensitivity.
|
|
