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

Explain dicotyledons, Dicotyledons (2,00,000 species) The dicot's are o...

Dicotyledons (2,00,000 species) The dicot's are of diverse nature. The leaves are net veined, stem contains ring of vascular bundles, cambium tissue is present so secondary

How do the sodium and potassium ions maintain the neuron, How do the sodium...

How do the sodium and potassium ions maintain the resting potential of the neuron? The plasma membrane of the neuron when at rest maintains an electric potential difference amo

What do you understand by exoskeleton, What do you understand by Exoskeleto...

What do you understand by Exoskeleton. Supporting structures of skeleton not surrounded by the body. Endoskeletal elements are secreted by an underlying epidermis and one side

How are the beings of the phylum annelida classified, Q. Concerning the occ...

Q. Concerning the occurrence of separated sexes how are the beings of the phylum Annelida classified? These beings may be dioecious (the majority of polychaetes) or hermaphrodi

Introduction to biodiversity, Biological diversity is the new buzzword, the...

Biological diversity is the new buzzword, the magic door to international funding and global travelling. We share the earth with million of other living beings. Just as we humans m

What is the meaning of paraplegia, What is the meaning of Paraplegia Pa...

What is the meaning of Paraplegia Paraplegia (from the Greek para, "alongside of," and plegia,  "stroke") is a condition in which both lower limbs are paralyzed (quadriplegia i

What are cytoplasmic inclusions, Cytoplasmic inclusions are cytoplasmic mol...

Cytoplasmic inclusions are cytoplasmic molecular aggregates, like as pigments, organic polymers and crystals. They are not considered cell organelles. Fat drops and glycogen gra

How dna molecules are formed, As a result of DNA replication two DNA molecu...

As a result of DNA replication two DNA molecules come into existence. Why is it not correct to assert that two "new" DNA molecules are created? What is the name given to the proces

What is the difference among sexual spores and gametes, What is the differe...

What is the difference among sexual spores and gametes? Do humans present sexual spores or gametes? Sexual spores are structures formed from meiosis with ploidy (number of chro

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