相关实验视频

Updated: Jul 12, 2026

Field Experiments of Pollination Ecology: The Case of Lycoris sanguinea var. sanguinea
07:19

Field Experiments of Pollination Ecology: The Case of Lycoris sanguinea var. sanguinea

Published on: November 25, 2016

欧洲玉米:费罗蒙多态或兄弟物种?

R T Cardé, W L Roelofs, R G Harrison

    Science (New York, N.Y.)
    |February 3, 1978
    PubMed
    概括

    欧洲玉米,Ostrinia nubilalis,表现出不同的 (Z) 和 (E) 费洛蒙菌株,这些菌株不会自由交配. 遗传分析显示,这些菌株是有差异的,可能代表兄弟物种.

    更多相关视频

    Embryo Microinjection and Knockout Mutant Identification of CRISPR/Cas9 Genome-Edited Helicoverpa Armigera (Hübner)06:37

    Embryo Microinjection and Knockout Mutant Identification of CRISPR/Cas9 Genome-Edited Helicoverpa Armigera (Hübner)

    Published on: July 1, 2021

    Laboratory Maintenance of the Lower Dipteran Fly Bradysia (Sciara) coprophila: A New/Old Emerging Model Organism04:26

    Laboratory Maintenance of the Lower Dipteran Fly Bradysia (Sciara) coprophila: A New/Old Emerging Model Organism

    Published on: April 19, 2024

    相关概念视频

    Frequency-dependent Selection01:21

    Frequency-dependent Selection

    When the fitness of a trait is influenced by how common it is (i.e., its frequency) relative to different traits within a population, this is referred to as frequency-dependent selection. Frequency-dependent selection may occur between species or within a single species. This type of selection can either be positive—with more common phenotypes having higher fitness—or negative, with rarer phenotypes conferring increased fitness.Positive Frequency-Dependent SelectionIn positive...
    Position-effect Variegation02:32

    Position-effect Variegation

    In 1928, a German botanist Emil Heitz observed the moss nuclei with a DNA binding dye. He observed that while some chromatin regions decondense and spread out in the interphase nucleus, others do not. He termed them euchromatin and heterochromatin, respectively. He proposed that the heterochromatin regions reflect a functionally inactive state of the genome. It was later confirmed that heterochromatin is transcriptionally repressed, and euchromatin is transcriptionally active chromatin.
    Background and Environment Affect Phenotype02:27

    Background and Environment Affect Phenotype

    Although the genetic makeup of an organism plays a major role in determining the phenotype, there are also several environmental factors, such as temperature, oxygen availability, presence of mutagens, that can alter an organism’s phenotype.
    An example of how genetic background affects phenotype can be seen in horses. The Extension gene in horses is responsible for their coat color. A wild-type gene (EE) produces black pigment in the coat, while a mutant gene (ee) produces red pigment. A...
    Understanding Species and Reproductive Barriers01:17

    Understanding Species and Reproductive Barriers

    A species is a group of organisms that interbreed and produce fertile offspring. Typically, individuals of the same species appear similar and share common characteristics due to their highly similar genomes. However, not all organisms that look alike are members of the same species. Various mechanisms keep most species discrete. While some mechanisms prevent reproductive behavior and fertilization (pre-zygotic isolation), others prevent the production of fertile offspring after mating has...