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

How the brain influences or controls immune system, How the brain influence...

How the brain influences or controls immune system Scientists are still working to determine to what degree, and how, the brain influences or controls immune system functions,

Determine the following term - amniote egg, Determine the following term - ...

Determine the following term - Amniote egg Eggs that shelter the developing embryo in a water-filled sac—the amnion. Characteristic of the amniote animals, which include reptil

What is constrictive pericarditis, Q. What is Constrictive pericarditis? ...

Q. What is Constrictive pericarditis? Constrictive pericarditis is the sequelae of chronic fibrosis and thickening of the pericardium as a result of chronic inflammation. E

Heart, how the blood is circulated with the help of heart

how the blood is circulated with the help of heart

Explain properties of colloidal systems - electric charge, Electric Charge ...

Electric Charge - Properties of Colloidal Systems Colloidal particles are electrically charged. Some colloidal particles carry a positive charge (+), others a negative charge (

Organisation of the marine ecosystem, Organisation of the Marine Ecosystem ...

Organisation of the Marine Ecosystem The oceans like lakes, exhibit zonations. First describe the various zones or regions of the oceans and then later deal with the biota occ

Describe how micrornas are able to influence gene expression, 1. Transcript...

1. Transcriptional analyses of eukaryotic cells reveal widespread production of RNA. Using specific examples describe how: a) microRNAs are able to influence gene expression.

Aortic allograft -biological valves, Aortic Allograft (Homograft) :  ...

Aortic Allograft (Homograft) :  In the earlier years fresh antibiotic preserved aortic allografts were tried. As the shelf life is limited, availability of all sizes at all t

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