A Brief Explanation of Mendels Law of Independent Assortment and What It States
Mendels Law of segregation states that each organism has two factors for each trait in their DNA. During gamete formation, these two factors separate, with each gamete receiving one factor. At fertilization, the factors combine with their partners once again; the offspring receiving one factor from each parent
Mendels Law of independent assortment states that members of one factor segregate from another factor for a different trait on a different chromosome independently.
Genes which are not linked illustrate Mendels law of independent assortment. Because the alleles for the genes are on different chromosomes, during gamete formation the genes have no effect on one another. A pea gamete having the allele for smooth seeds has no effect on whether the gamete has the allele for yellow or green seeds. When doing a punet square, the alleles of two or more traits that are not on the same can be treated as two or more monohybrid crosses. The presence of one non-linked allele has no effect on the presence of another non-linked allele for another trait in gamete formation.
Order custom essay A Brief Explanation of Mendels Law of Independent Assortment and What It States with free plagiarism report
450+ experts on 30 subjects
Starting from 3 hours delivery
When considering genes which are linked (on the same chromosome), only Mendels law of segregation applies. During gamete formation, the chromosomes separate and each sex cell gets one version of each chromosome pair. When two alleles for two respective traits are present on this chromosome, these traits are said to be linked; in that a gamete with the chromosome will always contain both traits (baring mutations). A gamete with the one of these alleles will always possess the other linked allele as well (baring mutations).
Crossing over can be discussed through Mendels law of segregation. Crossing over occurs when an allele which shares a chromosome with a linked allele, breaks off and changes places with its partner on another chromosome. This mutation allows for variation in the phenotypic expression of linked alleles. It relates to the law of segregation through the above discussion of linked genes. In that it is simply a mutation which prevents two traits from always being exhibited together.
Sex linkage varies greatly by species. However in humans, I will discuss it through the law of segregation. The females sex cells all have the X chromosome, for this is the only version of the sex chromosome that females posses. Meanwhile half of male sex cells contain the X chromosome and the other half contain the Y chromosome. Which male cells contain the X or Y is totally random and dependent on the law of segregation. If a male sex cells with a Y chromosome fertilizes the egg, a male is formed. If a male sex cell with an X chromosome fertilizes the egg, a female is formed.
Down syndrome results when a sex cell receives two chromosome 21s. Therefore it is essentially a mix up in the law of segregation. When the sex cell with the 2 chromosome 21s is fertilized (or fertilizes) the result is a cell with 3 chromosome 21s. Thus the child has 3 sets of information for all traits on that chromosome resulting in problems for its cells.
Turner syndrome results when a female sex cell (egg) does not receive an x or y chromosome. Therefore this is essentially another mix up in the law of segregation. If this egg is fertilized with a male sex cell with an X chromosome, the result is a normal female (because only 1 X is active in females). However, if a sperm cell with a Y chromosome impregnates the egg, the child does not receive all the information required for it has no X chromosome.
Cite this Page
A Brief Explanation of Mendels Law of Independent Assortment and What It States. (2023, Jun 28). Retrieved from https://phdessay.com/a-brief-explanation-of-mendels-law-of-independent-assortment-and-what-it-states/
Run a free check or have your essay done for you
