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Haplogroup S (mtDNA)
In human genetics, Haplogroup S is a human mitochondrial DNA (mtDNA) haplogroup found only among Indigenous Australians. It is a descendant of macrohaplogroup N. Origin Haplogroup S mtDNA evolved within Australia between 64,000 and 40,000 years ago (51 kya). Distribution It is found in the Indigenous Australian population. Haplogroup S2 found in Willandra Lakes human remain WLH4 dated back Late Holocene (3,000-500 years ago). Subclades Tree This phylogenetic tree of haplogroup S subclades is based on the paper by Mannis van Oven and Manfred Kayser ''Updated comprehensive phylogenetic tree of global human mitochondrial DNA variation'' and subsequent published research. ''The TMRCA for haplogroup S is between 49 and 51 KYA'' according to Nano Nagle's ''Aboriginal Australian mitochondrial genome variation – an increased understanding of population antiquity and diversity'' publication that published in 2017. *S (64-40 kya) in Australia **S1 (53-32 kya) in Australia ***S1a (44- ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Human Mitochondrial DNA (mtDNA) Haplogroup
In human genetics, a human mitochondrial DNA haplogroup is a haplogroup defined by differences in human mitochondrial DNA. Haplogroups are used to represent the major branch points on the mitochondrial phylogenetic tree. Understanding the evolutionary path of the female lineage has helped population geneticists trace the matrilineal inheritance of modern humans back to human origins in Africa and the subsequent spread around the globe. The letter names of the haplogroups (not just mitochondrial DNA haplogroups) run from A to Z. As haplogroups were named in the order of their discovery, the alphabetical ordering does not have any meaning in terms of actual genetic relationships. The hypothetical woman at the root of all these groups (meaning just the mitochondrial DNA haplogroups) is the matrilineal most recent common ancestor (MRCA) for all currently living humans. She is commonly called Mitochondrial Eve. The rate at which mitochondrial DNA mutates is known as the mitochon ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Haplogroup N (mtDNA)
Haplogroup N is a human mitochondrial DNA (mtDNA) clade. A macrohaplogroup, its descendant lineages are distributed across many continents. Like its sibling macrohaplogroup M, macrohaplogroup N is a descendant of the haplogroup L3. All mtDNA haplogroups found outside of Africa are descendants of either haplogroup N or its sibling haplogroup M. M and N are the signature maternal haplogroups that define the theory of the recent African origin of modern humans and subsequent early human migrations around the world. The global distribution of haplogroups N and M indicates that there was likely at least one major prehistoric migration of humans out of Africa, with both N and M later evolving outside the continent. Origins There is widespread agreement in the scientific community concerning the African ancestry of haplogroup L3 (haplogroup N's parent clade). However, whether or not the mutations which define haplogroup N itself first occurred within Asia or Africa has been a subject ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Human Genetics
Human genetics is the study of inheritance as it occurs in human beings. Human genetics encompasses a variety of overlapping fields including: classical genetics, cytogenetics, molecular genetics, biochemical genetics, genomics, population genetics, developmental genetics, clinical genetics, and genetic counseling. Genes are the common factor of the qualities of most human-inherited traits. Study of human genetics can answer questions about human nature, can help understand diseases and the development of effective treatment and help us to understand the genetics of human life. This article describes only basic features of human genetics; for the genetics of disorders please see: medical genetics. Genetic differences and inheritance patterns Inheritance of traits for humans are based upon Gregor Mendel's model of inheritance. Mendel deduced that inheritance depends upon discrete units of inheritance, called factors or genes. Autosomal dominant inheritance Autosomal tr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Indigenous Australians
Indigenous Australians or Australian First Nations are people with familial heritage from, and membership in, the ethnic groups that lived in Australia before British colonisation. They consist of two distinct groups: the Aboriginal peoples of the Australian mainland and Tasmania, and the Torres Strait Islander peoples from the seas between Queensland and Papua New Guinea. The term Aboriginal and Torres Strait Islander peoples or the person's specific cultural group, is often preferred, though the terms First Nations of Australia, First Peoples of Australia and First Australians are also increasingly common; 812,728 people self-identified as being of Aboriginal and/or Torres Strait Islander origin in the 2021 Australian Census, representing 3.2% of the total population of Australia. Of these indigenous Australians, 91.4% identified as Aboriginal; 4.2% identified as Torres Strait Islander; while 4.4% identified with both groups. [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sahul Map
__NOTOC__ Sahul (), also called Sahul-land, Meganesia, Papualand and Greater Australia, was a paleocontinent that encompassed the modern-day landmasses of mainland Australia, Tasmania, New Guinea, and the Aru Islands. Sahul was in the south-western Pacific Ocean, located appropriately north to south between the Equator and the 44th parallel south and west to east between the 112th and the 152nd meridians east. Sahul was separated from Sunda to its west by the Wallacean Archipelago. At its largest, when ocean levels were at their lowest, it was approximately in size. After the last Ice Age global temperatures increased and sea levels gradually rose, flooding the land bridge and separating mainland Australia from New Guinea and Tasmania. New Guinea was separated from the Australian mainland approximately 8,000 years ago, and Tasmania approximately 6,000 years ago. Sahul hosted a large variety of unique fauna that evolved independently from the rest of the world. Most notabl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Genealogical DNA Test
A genealogical DNA test is a DNA-based test used in genetic genealogy that looks at specific locations of a person's genome in order to find or verify ancestral genealogical relationships, or (with lower reliability) to estimate the ethnic mixture of an individual. Since different testing companies use different ethnic reference groups and different matching algorithms, ethnicity estimates for an individual vary between tests, sometimes dramatically. Three principal types of genealogical DNA tests are available, with each looking at a different part of the genome and being useful for different types of genealogical research: autosomal (atDNA), mitochondrial (mtDNA), and Y-DNA. Autosomal tests may result in a large number of DNA matches to both males and females who have also tested with the same company. Each match will typically show an estimated degree of relatedness, i.e., a close family match, 1st-2nd cousins, 3rd-4th cousins, etc. The furthest degree of relationship is u ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Genetic Genealogy
Genetic genealogy is the use of genealogical DNA tests, i.e., DNA profiling and DNA testing, in combination with traditional genealogical methods, to infer genetic relationships between individuals. This application of genetics came to be used by family historians in the 21st century, as DNA tests became affordable. The tests have been promoted by amateur groups, such as surname study groups or regional genealogical groups, as well as research projects such as the Genographic Project. As of 2019, about 30 million people had been tested. As the field developed, the aims of practitioners broadened, with many seeking knowledge of their ancestry beyond the recent centuries, for which traditional pedigrees can be constructed. History The investigation of surnames in genetics can be said to go back to George Darwin, a son of Charles Darwin and Charles' first cousin Emma Darwin. In 1875, George Darwin used surnames to estimate the frequency of first-cousin marriages and calculated t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Human Mitochondrial Genetics
Human mitochondrial genetics is the study of the genetics of human mitochondrial DNA (the DNA contained in human mitochondria). The human mitochondrial genome is the entirety of hereditary information contained in human mitochondria. Mitochondria are small structures in cells that generate energy for the cell to use, and are hence referred to as the "powerhouses" of the cell. Mitochondrial DNA (mtDNA) is not transmitted through nuclear DNA (nDNA). In humans, as in most multicellular organisms, mitochondrial DNA is inherited only from the mother's ovum. There are theories, however, that paternal mtDNA transmission in humans can occur under certain circumstances. Mitochondrial inheritance is therefore non-Mendelian, as Mendelian inheritance presumes that half the genetic material of a fertilized egg (zygote) derives from each parent. Eighty percent of mitochondrial DNA codes for mitochondrial RNA, and therefore most mitochondrial DNA mutations lead to functional problems, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Population Genetics
Population genetics is a subfield of genetics that deals with genetic differences within and between populations, and is a part of evolutionary biology. Studies in this branch of biology examine such phenomena as adaptation, speciation, and population structure. Population genetics was a vital ingredient in the emergence of the modern evolutionary synthesis. Its primary founders were Sewall Wright, J. B. S. Haldane and Ronald Fisher, who also laid the foundations for the related discipline of quantitative genetics. Traditionally a highly mathematical discipline, modern population genetics encompasses theoretical, laboratory, and field work. Population genetic models are used both for statistical inference from DNA sequence data and for proof/disproof of concept. What sets population genetics apart from newer, more phenotypic approaches to modelling evolution, such as evolutionary game theory and adaptive dynamics, is its emphasis on such genetic phenomena as dominance, epi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
