Nettie Maria Stevens (Cavendish (Vermont), 7 de julio de 1861 – Baltimore, 4 de mayo de 1912) fue una genetista estadounidense de ascendencia inglesa y sueca. Fue la primera investigadora en describir las bases cromosómicas que determinan el sexo.Amplió exitosamente los campos de la embriología y la citogenética

The XY sex-determination system is a sex-determination system used to classify many mammals, including humans, some insects (), some snakes, some fish (), and some plants (Ginkgo tree). In this system, the sex of an individual is determined by a pair of sex chromosomes.Females have two of the same kind of sex chromosome (XX), and are called the …

A sex-determination system is a biological system that determines the development of sexual characteristics in an organism. Most organisms that create their offspring using sexual reproduction have two sexes.. In some species there are hermaphrodites. There are also some species that are only one sex due to parthenogenesis, the act of a female reproducing without …

Hermaphroditismus (griechisch von Hermes und Aphrodite, siehe dazu Hermaphroditos), Zwittrigkeit oder Zwittertum bezeichnet in der Biologie den Zustand von doppeltgeschlechtlichen Individuen, also Individuen einer Art mit männlicher und weiblicher Geschlechtsausprägung, die sowohl männliche als auch weibliche Keimzellen bzw. Geschlechtsorgane bilden. ...

A sex chromosome (also referred to as an allosome, heterotypical chromosome, gonosome, heterochromosome, or idiochromosome) is a chromosome that differs from an ordinary autosome in form, size, and behavior. The human sex chromosomes, a typical pair of mammal allosomes, determine the sex of an individual created in sexual reproduction.Autosomes differ from …

The League of Women Voters (LWV or the League) is a nonprofit, nonpartisan political organization in the United States.Founded in 1920, its ongoing major activities include registering voters, providing voter information, and advocating for voting rights. In addition, the LWV works with partners that share its positions and supports a variety of progressive public policy …

Eunice Mary Kennedy Shriver DSG (July 10, 1921 – August 11, 2009) was an American philanthropist and a member of the Kennedy family.She was the founder of the Special Olympics, a sports organization for persons with physical and intellectual disabilities.For her efforts on behalf of disabled people, Shriver was awarded the Presidential Medal of Freedom in 1984.

Early life. Born to Andrew Kenley Wilson and Constance (née Coolidge) in Pittsburgh, Pennsylvania, Wilson's family moved to Alabama when she was still very young. She earned a degree from Alabama Normal College (now the University of West Alabama), and became a school teacher for young children, soon leaving to pursue a film career.. In 1915, Wilson moved …

Acontecimientos. 1486: en Córdoba (España), los Reyes Católicos expiden la Pragmática que manda observar y guardar el Cuaderno de las Leyes Nuevas de la Santa Hermandad.; 1543: las tropas francesas invaden Luxemburgo.; 1558: en Inglaterra, un tornado arrasa la villa de Nottingham, destruye todas las casas e iglesias del pueblo y arroja los árboles hasta a 60 m …

1861 – Nettie Stevens, American geneticist (d. 1912) 1869 – Rachel Caroline Eaton, American academic (d. 1938) 1869 – Fernande Sadler, French painter and mayor (d. 1949) 1874 – Erwin Bumke, German lawyer and jurist (d. 1945) 1880 – Otto Frederick Rohwedder, American engineer, invented sliced bread (d. 1960)