Explain the mendel''s laws in genetics, Biology

Assignment Help:

Explain the Mendel's Laws in genetics?

Based on the results of his experiments, Mendel proposed three laws regarding the inheritance of traits: the Law of Segregation, the Law of Independent Assortment, and the Law of Dominance.

The first principle proposed by Mendel, the Law of Segregation, states that "factors" responsible for inheritance of traits remain separate in the offspring, rather than blending . Because traits not apparent in the F1 generation reappeared in the F2 generation, and the F2 generation also had two factors, Mendel concluded that each parent carried two factors that segregate, or separate, during the formation of sperm or egg cells so that they each carry only one factor; therefore the offspring had two factors, the same as the parent.
Since Mendel studied a number of traits, he found that alleles governing different traits, such as position of flowers along the stem; position, shape, and color of the pod; height of the plant; seed texture, seed color, and seed coat color, segregate independently from the alleles that govern another trait. This formed the basis of the second principle, the Law of Independent Assortment. We will see that this law applies only to genes found on different chromosomes.

The third principle, the Law of Dominance, was a result of Mendel's discovery that when two strains were cross-pollinated, one factor in a pair, the dominant factor, may mask the other, so that the dominant trait is always observed in the F1 generation. He called a factor recessive if the trait did not appear until the F2 generation. Some traits were found to exhibit incomplete dominance; that is, heterozygous plants had phenotypes intermediate between the dominant and the recessive. An example is a dominant red flowered plant and recessive white-flowered producing pink-flowered offspring. If dominant traits produce different phenotypes, and both appear in heterozygotes, the traits are called codominant.

539_variations on the mendelian theme.png

There are traits such as skin color in humans that have more than two phenotypes and result from contributions from two or more genes. This condition is called polygenic inheritance. In its simplest form, two genes code for the same trait; an example is kernel color in wheat, where two genes have two alleles, R for red pigment and R' for no pigment at all. The resulting phenotypes exhibit incomplete dominance as with heterozygous single alleles, but there are more shades of red because there are more genes contributing to the trait.


Related Discussions:- Explain the mendel''s laws in genetics

Muscle cells, explain why it is essential that muscle cells, during anaerob...

explain why it is essential that muscle cells, during anaerobic respiration, convert pyruvic acid(pyruvate) into lactic acid, even though the conversion results in an accumulation

Differential reinforcement of other behaviour, Differential reinforcement o...

Differential reinforcement of other behaviour (DRO) This is used to decrease frequent behaviour by reinforcing any behaviour other than the undesired one. An instance would be r

Define freeze concentration, Define Freeze Concentration? This process ...

Define Freeze Concentration? This process has been known for many years and has been applied commercially to orange juice. However, high processing costs due largely to losses

How dietary constituents affecting the calcium absorption, How dietary cons...

How dietary constituents affecting the calcium absorption? Several dietary constituents have an effect on calcium absorption. The differences in fractional absorption from diff

How does the pancreatic juice help the digestion of lipids, Q. How does the...

Q. How does the pancreatic juice help the digestion of lipids? What is the involved enzyme? The enzyme pancreatic lipase is present in the pancreatic juice this enzyme breaks t

Ganglia - organisation of nervous system, Ganglia - Organisation of Nervous...

Ganglia - Organisation of Nervous System In between higher non-chordates with a central nervous system, you will observe that the association neurons and motor neurons are con

What do you mean by dicoumarol, Q. What is dicoumarol? How does this substa...

Q. What is dicoumarol? How does this substance act in the clotting process and what are some examples of its toxicity? Coumarinic anticoagulants cannot be administered during p

Describe the neuropsychological assessment of infants, Describe the Neurops...

Describe the Neuropsychological Assessment of Infants Neuropsychological Assessment of Infants and Young Children followed by the developmental Concepts Unique to Infants and

Explain transgenic organisms, As the functions of individual genes become k...

As the functions of individual genes become known, the power of this new biology can be used to change organisms in predictable and desirable pathways.  Organisms which have been c

Write Your Message!

Captcha
Free Assignment Quote

Assured A++ Grade

Get guaranteed satisfaction & time on delivery in every assignment order you paid with us! We ensure premium quality solution document along with free turntin report!

All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd