Difference Between Law of Segregation and Law of Independent Assortment (With Table)

If you look really closely, science can be found almost anywhere. 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. The Law of Segregation and the Law of Independent Assortment are two of these laws. While these two are related, there are considerable differences between them. 

Law of Segregation vs Law of Independent Assortment 

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. These copies are then said to reunite after fertilization. 

On the other hand, the Law of Independent Assortment signifies that the genes independently pass on to the offspring without prior segregation into copies. According to this law, different genes related to different traits can be passed on to the end result.  

Comparison Table Between Law of Segregation and Law of Independent Assortment 

Parameters of Comparison Law of Segregation Law of Independent Assortment 
Meaning  It denotes the theory of the separation of copies of genes before reproduction.  It denotes those multiple genes pertaining to similar traits can be passed on to the offspring without any segregation before.  
Ratio of offspring  3:1 is the ratio. 9:3:3:1 is the ratio.  
Position  It is the third law given by Mendel.  It is the second law propounded by Mendel and comes after the previous one.  
States about Segregation of alleles Behavior and end result of alleles 
Number of alleles Only one allele of one gene is passed on to the offspring. Multiple genes pertaining to similar traits can be passed on to the offspring. 

What is Law of Segregation? 

The Law of Segregation outlines that when reproduction occurs, the copies of particular genes separate from one another and appear again after fertilization. This can better be understood by looking at the experiment Mendel conducted.  

  • He chose two plants having different genes for a similar trait, such as a plant with red flowers and a plant with yellow flowers. 
  •  After choosing these plants, he made them reproduce with one another and waited for a few days.  
  • After a few days, the flowers which took birth out of these two parental plants had red color only.  
  • But after these plants, which were having a red color, were fertilized by themselves, the end result plants had both white and red colors in them.  
  • The ratio of plants having these two colors was 3:1 roughly. 

 Based on this theory, Mendel stated that in the first generation of offspring, the less dominant trait, i.e., the white color disappeared and came back in the second generation. Segregation of genes in this manner paved the way for the conceptualization of the Law of Segregation.  

What is Law of Independent Assortment? 

This particular law states that two or more different traits having different genes can come together as a unit and will be selected randomly and independently after the fertilization. This can better be explained by the following example- 

  • He chose two plants, one with pink color and tall height while one with blue color and dwarf height.  
  • When these were made fertilized, the first generation appeared to be all having pink colors and tall height. This proved that pink as color and tall as height were dominant traits and suppressed the other traits.  
  • But when this first generation was left to fertilize, the second-generation plants showed all traits in different ratios.  
  • There were pink plants with tall height, pink plants with dwarf height, blue plants with tall height, and blue plants with dwarf height.  

A similar experiment was carried out by Mendel, which led him to believe in the Law of Independent Assortment.  

Main Differences Between Law of Segregation and Law of Independent Assortment 

  1. The Law of Segregation stands as the third rule of inheritance propounded by Mendel, while the Law of Independent Assortment stands as the second rule of inheritance. 
  2. The Law of Segregation states that the alleles of a gene get separated from the original gene and get passed on to the offspring by way of reproduction, while the Law of Independent assortment states that a gene can pass on more than one allele to the offspring by way of reproduction.  
  3. The ratio of offspring in the former happens to be 3:1, while in the latter, this ratio happens to be 9:3:3:1.  
  4. The law of Segregation talks about the separation of alleles, while the Law of Independent Assortment talks about the behavior that these alleles show after reaching an offspring.  
  5. In the law of Segregation, only one copy of one gene can be passed on, while in the Law of Independent Assortment, many copies can be passed on.  

Conclusion  

The process by which a kid inherits genetic data from a parent is popularly known as inheritance. 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.  

This understanding of inheritance was made possible by Gregor Mendel, a scientist who developed Mendel’s rules of inheritance which assisted the common people to understand inheritance. By propounding these rules, he made an outline for us to grasp a better understanding of this concept.  

References 

  1. http://v3r.esp.org/foundations/genetics/classical/holdings/v/hdv-00.pdf  
  2. https://rave.ohiolink.edu/etdc/view?acc_num=csu1611776149127827
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