What is the difference between independent assortment and random segregation

Science offers an answer for everything, from the appearance of tears while chopping an onion to the growth of a tiny seed into a fully formed tree. Various notable scientists and ideologists have offered their thoughts and interpretations on a wide range of scientific topics from time to time.

Gregor John Mendel was one of these scientists, who in the 18th century, provided the world three genetic principles. While these two are related, there are considerable differences between them. The difference between the Law of Segregation and the Law of Independent Assortment is that in the former principle, Mendel has stated that all the genes have a copy to them, which separates from the original gene during reproduction, and both the parents pass on one such copy to the offspring.

While in the law of Independent Assortment, he has stated that copies of various genes get separated from one another in an independent manner.

Law of Segregation outlines that when reproduction takes place, each of the parents passes on one trait to their offspring.

This trait is not passed by the original gene but by the copies of that gene, popularly known as an allele. These copies are separated before being passed on, and it occurs so that no trait is repeated or so that only one allele is carried on further in the offspring. Mendel said that factors, later called genes, normally occur in pairs in ordinary body cells, yet segregate during the formation of sex cells.

Each member of the pair becomes part of the separate sex cell. After Mendel self-fertilized the F1 generation and obtained an F2 generation with a ratio, he correctly theorized that genes can be paired in three different ways for each trait: AA, aa, and Aa. The capital A represents the dominant factor while the lowercase a represents the recessive. The resulting hybrids in the F1 generation all had violet flowers.

In the F2 generation, approximately three-quarters of the plants had violet flowers, and one-quarter had white flowers. Mendel stated that each individual has two alleles for each trait, one from each parent. One allele is given by the female parent and the other is given by the male parent. The two factors may or may not contain the same information.

If the two alleles are identical, the individual is called homozygous for the trait. If the two alleles are different, the individual is called heterozygous. The presence of an allele does not promise that the trait will be expressed in the individual that possesses it. In heterozygous individuals, the only allele that is expressed is the dominant.

The recessive allele is present, but its expression is hidden. The genotype of an individual is made up of the many alleles it possesses. Mendel also analyzed the pattern of inheritance of seven pairs of contrasting traits in the domestic pea plant. He did this by cross-breeding dihybrids; that is, plants that were heterozygous for the alleles controlling two different traits. Mendel then crossed these dihybrids.

If it is inevitable that round seeds must always be yellow and wrinkled seeds must be green, then he would have expected that this would produce a typical monohybrid cross: 75 percent round-yellow; 25 percent wrinkled-green. But, in fact, his mating generated seeds that showed all possible combinations of the color and texture traits. Today we know that this rule holds only if the genes are on separate chromosomes. In a heterozygote, the allele which masks the other is referred to as dominant, while the allele that is masked is referred to as recessive.

Most familiar animals and some plants have paired chromosomes and are described as diploid. They have two versions of each chromosome: one contributed by the female parent in her ovum and one by the male parent in his sperm. These are joined at fertilization.

The ovum and sperm cells the gametes have only one copy of each chromosome and are described as haploid. Recessive traits are only visible if an individual inherits two copies of the recessive allele : The child in the photo expresses albinism, a recessive trait.

Rather than both alleles contributing to a phenotype, the dominant allele will be expressed exclusively. The recessive trait will only be expressed by offspring that have two copies of this allele; these offspring will breed true when self-crossed. By definition, the terms dominant and recessive refer to the genotypic interaction of alleles in producing the phenotype of the heterozygote. The key concept is genetic: which of the two alleles present in the heterozygote is expressed, such that the organism is phenotypically identical to one of the two homozygotes.

It is sometimes convenient to talk about the trait corresponding to the dominant allele as the dominant trait and the trait corresponding to the hidden allele as the recessive trait. However, this can easily lead to confusion in understanding the concept as phenotypic.

This will subsequently confuse discussion of the molecular basis of the phenotypic difference. Dominance is not inherent. One allele can be dominant to a second allele, recessive to a third allele, and codominant to a fourth.

If a genetic trait is recessive, a person needs to inherit two copies of the gene for the trait to be expressed. Thus, both parents have to be carriers of a recessive trait in order for a child to express that trait. Instead, several different patterns of inheritance have been found to exist. Apply the law of segregation to determine the chances of a particular genotype arising from a genetic cross.

Observing that true-breeding pea plants with contrasting traits gave rise to F 1 generations that all expressed the dominant trait and F 2 generations that expressed the dominant and recessive traits in a ratio, Mendel proposed the law of segregation. The law of segregation states that each individual that is a diploid has a pair of alleles copy for a particular trait. 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.

As evident from the title, what is the difference between independent assortment and random segregation in meiosis? Its kind of screwing me over I was able to understand it before Random Segregation: The alleles go through meiosis to create gametes, they will segregate from one another, and each of the haploid gametes will end up with only one allele i. Independent assortment is when you are looking at how the alleles of two genes separate.

The alleles will assort themselves independently of one another when the haploid gametes are formed in meiosis. Thanks for the help! Each haploid gamete ends up with a different combination of alleles of these two genes i. You must log in or register to reply here.