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WHICH ARE THE 4 LAWS OF HEREDITY.(MENDEL'S LAW) STATE EXAMPLES FOR EACH

Law of Dominance: In heterozygous condition, one of the factors expresses itself (Dominant character) and prevents the expression of other factor (Recessive character).

Mendel's Law of Segregation (MONOHYBRID CROSS)

    Mendel crossed true-breeding plants that differed for a given character
    A monohybrid cross involves one (mono) character and different (hybrid) traits.
    Pollen from true-breeding pea plants with purple flowers (one trait) was placed on stigmas of true-breeding plants with white flowers (another trait).
    The F1 seeds were all purple; the white flower trait failed to appear at all.
    Because the purple flower trait completely masks the white flower trait when true-breeding plants are crossed, the purple flower trait is called dominant, and the white flower trait is called recessive.
    The F1 plants were allowed to self-pollinate.
    This step was the monohybrid cross. (or the F1 cross).
    The progeny, called F2, were examined: roughly 1/4 were white, and 3/4 were purple.
    Mendel proposed that the units responsible for inheritance were discrete particles - particulate theory.

   
Mendel's Law of Independent Assortment

    The second law describes the outcome of dihybrid (two character) crosses, or hybrid crosses involving additional characters.
    A dihybrid is an individual that is a double heterozygote (e.g., with the genotype RrYy - round seed, yellow seed).
    Mendel's second law states that the Rr alleles assort into gametes independently of the Yy alleles.
    The dihybrid, RrYy, produces gametes that have one allele of each gene.
    Four different gametes are possible and will be produced in equal proportions: RY, Ry, rY, and ry.
    Random fertilization of gametes yields the outcome visible in the Punnett square. Note its 4x4 table construction to accommodate 16 possible phenotypes.
    Filling in the table and adding the like cells reveals a 9:3:3:1 ratio of the four possible phenotypes: (Round, Yellow - Round, Green - Wrinkled, Yellow - Wrinkled, Green.)
    The Law of Independent Assortment states that alleles of different genes assort independently of one another during gamete formation.
    In fact, this law is not always true - The law of independent assortment is accurate for genes that are on separate chromosomes, but not necessarily for genes that are on the same chromosome.
    Genes that are close to each other on the same chromosome tend to stay together, but crossing over during meiosis may separate them.


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