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Atavisms can occur in a number of different ways, including by the re-expression of latent genes for ancestral phenotypes as a result of mutation, or by the shortening or prolongation of the time allocated for the ontogenesis of a particular trait during development. autapomorphy autoallopolyploid autopolyploid autozygote
Family History in the Genes : Trace Your DNA and Grow Your Family Tree. Kew, UK: National Archives. ISBN 978-1-905615-12-4. Shawker, Thomas H. (2004). Unlocking Your Genetic History : A Step-by-Step Guide to Discovering Your Family's Medical and Genetic Heritage. Nashville, TN: Rutledge Hill Press. ISBN 978-1-4016-0144-7.
The human genome is the total collection of genes in a human being contained in the human chromosome, composed of over three billion nucleotides. [2] In April 2003, the Human Genome Project was able to sequence all the DNA in the human genome, and to discover that the human genome was composed of around 20,000 protein coding genes.
Eukaryotic genes often have introns that are much larger than their exons, [66] [67] and those introns can even have other genes nested inside them. [68] Associated enhancers may be many kilobase away, or even on entirely different chromosomes operating via physical contact between two chromosomes.
Alleles are different variations of specific genes. They determine things like hair colour, skin tone, eye colour and blood type; in other words, all the genetic traits that vary between individuals. Genetic drift does not introduce new alleles to a population, but it can reduce variation within a population by removing an allele from the gene ...
Sometimes, the expression of dormant genes can be induced by artificial stimulation. Atavisms have been observed in humans, such as with infants born with vestigial tails (called a "coccygeal process", "coccygeal projection", or "caudal appendage"). [8] Atavism can also be seen in humans who possess large teeth, like those of other primates. [9]
Genes are like sentences made of the "letters" of the nucleotide alphabet, between them genes direct the physical development and behavior of an organism. Genes are like a recipe or instruction book, providing information that an organism needs so it can build or do something - like making an eye or a leg, or repairing a wound.
Population genetics is a subfield of genetics that deals with genetic differences within and among populations, and is a part of evolutionary biology.Studies in this branch of biology examine such phenomena as adaptation, speciation, and population structure.