What is the difference between independent assortment and segregation

After performing a dihybrid cross, the ratio between the offspring will be The inheritance of two characters, the pod color and the pod shape according to the law of independent assortment is shown in figure 2. Law of Segregation: Law of segregation is a principle described by Gregor Mendel in which the two copies of each of the hereditary factor segregate from each other during the production of gametes. Law of Independent Assortment: Law of independent assortment is a principle described by Gregor Mendel in which the individual hereditary factors are independently assorted during the production of gametes when two or more factors are inherited.

Law of Segregation: The law of segregation is the first law of Mendelian inheritance. Law of Independent Assortment: The law of independent assortment is the second law of Mendelian inheritance. Law of Segregation: Law of segregation describes the behavior of nonhomologous chromosomes. Law of Independent Assortment: Law of independent assortment describes the behavior of alleles.

Law of Segregation: The ratio between the offspring is Law of Independent Assortment: The ratio between the offspring is It is important to note that there is an exception to the law of independent assortment for genes that are located very close to one another on the same chromosome because of genetic linkage.

Further Exploration Concept Links for further exploration gene principle of segregation allele genotype phenotype dihybrid cross gamete diploid chromosome haploid meiosis recombination linkage Principles of Inheritance principle of uniformity.

Related Concepts You have authorized LearnCasting of your reading list in Scitable. Do you want to LearnCast this session? This article has been posted to your Facebook page via Scitable LearnCast. The entire process of heredity is dependent on inheritance, which is why the offspring look like their parents. This indicates that individuals of the same family share comparable qualities as a result of heredity.

This not only applies to humans but plants and animals also. By propounding these rules, he made an outline for us to grasp a better understanding of this concept. Skip to content If you look really closely, science can be found almost anywhere. It denotes those multiple genes pertaining to similar traits can be passed on to the offspring without any segregation before.

Each parent passes an allele at random to their offspring resulting in a diploid organism. The allele that contains the dominant trait determines the phenotype of the offspring. In essence, the law states that copies of genes separate or segregate so that each gamete receives only one allele. For the F 2 generation of a monohybrid cross, the following three possible combinations of genotypes could result: homozygous dominant, heterozygous, or homozygous recessive.

The equal segregation of alleles is the reason we can apply the Punnett square to accurately predict the offspring of parents with known genotypes. The behavior of homologous chromosomes during meiosis can account for the segregation of the alleles at each genetic locus to different gametes.

As chromosomes separate into different gametes during meiosis, the two different alleles for a particular gene also segregate so that each gamete acquires one of the two alleles. Independent assortment allows the calculation of genotypic and phenotypic ratios based on the probability of individual gene combinations.

Use the probability or forked line method to calculate the chance of any particular genotype arising from a genetic cross. The independent assortment of genes can be illustrated by the dihybrid cross: a cross between two true-breeding parents that express different traits for two characteristics. Consider the characteristics of seed color and seed texture for two pea plants: one that has green, wrinkled seeds yyrr and another that has yellow, round seeds YYRR.

Therefore, the F 1 generation of offspring all are YyRr. For the F2 generation, the law of segregation requires that each gamete receive either an R allele or an r allele along with either a Y allele or a y allele.

The law of independent assortment states that a gamete into which an r allele sorted would be equally likely to contain either a Y allele or a y allele. Thus, there are four equally likely gametes that can be formed when the YyRr heterozygote is self-crossed as follows: YR, Yr, yR, and yr. These are the offspring ratios we would expect, assuming we performed the crosses with a large enough sample size. Independent assortment of 2 genes : This dihybrid cross of pea plants involves the genes for seed color and texture.

Because of independent assortment and dominance, the dihybrid phenotypic ratio can be collapsed into two ratios, characteristic of any monohybrid cross that follows a dominant and recessive pattern. Ignoring seed color and considering only seed texture in the above dihybrid cross, we would expect that three-quarters of the F 2 generation offspring would be round and one-quarter would be wrinkled.

Similarly, isolating only seed color, we would assume that three-quarters of the F 2 offspring would be yellow and one-quarter would be green. The sorting of alleles for texture and color are independent events, so we can apply the product rule. These proportions are identical to those obtained using a Punnett square. When more than two genes are being considered, the Punnett-square method becomes unwieldy. It would be extremely cumbersome to manually enter each genotype.

For more complex crosses, the forked-line and probability methods are preferred. To prepare a forked-line diagram for a cross between F 1 heterozygotes resulting from a cross between AABBCC and aabbcc parents, we first create rows equal to the number of genes being considered and then segregate the alleles in each row on forked lines according to the probabilities for individual monohybrid crosses.

We then multiply the values along each forked path to obtain the F 2 offspring probabilities. Note that this process is a diagrammatic version of the product rule. The values along each forked pathway can be multiplied because each gene assorts independently.

For a trihybrid cross, the F 2 phenotypic ratio is Independent assortment of 3 genes : The forked-line method can be used to analyze a trihybrid cross. Here, the probability for color in the F2 generation occupies the top row 3 yellow:1 green. The probability for shape occupies the second row 3 round:1 wrinked , and the probability for height occupies the third row 3 tall:1 dwarf.

The probability for each possible combination of traits is calculated by multiplying the probability for each individual trait. While the forked-line method is a diagrammatic approach to keeping track of probabilities in a cross, the probability method gives the proportions of offspring expected to exhibit each phenotype or genotype without the added visual assistance.

To fully demonstrate the power of the probability method, however, we can consider specific genetic calculations. For instance, for a tetrahybrid cross between individuals that are heterozygotes for all four genes, and in which all four genes are sorting independently in a dominant and recessive pattern, what proportion of the offspring will be expected to be homozygous recessive for all four alleles?

Rather than writing out every possible genotype, we can use the probability method. Genes that are located on separate non-homologous chromosomes will always sort independently. However, each chromosome contains hundreds or thousands of genes organized linearly on chromosomes like beads on a string. The segregation of alleles into gametes can be influenced by linkage, in which genes that are located physically close to each other on the same chromosome are more likely to be inherited as a pair.

Homologous chromosomes possess the same genes in the same linear order. The alleles may differ on homologous chromosome pairs, but the genes to which they correspond do not. In preparation for the first division of meiosis, homologous chromosomes replicate and synapse.