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

Show foods that damage gi mucosa, Q. Show Foods that damage GI mucosa? ...

Q. Show Foods that damage GI mucosa? Foods that damage GI mucosa: A number of spices, herbs and other condiments have been found to have little or no irritating effect on the m

Ilustrate about corvous caurinus, When we watch animals in the wild, most o...

When we watch animals in the wild, most often we see them foraging for food. The foraging behaviour of animals has been a focus of behavioural studies for many decades. Natura

Ovarian androgens, Normal 0 false false false EN-IN X...

Normal 0 false false false EN-IN X-NONE X-NONE MicrosoftInternetExplorer4

What do you understand by term - acanthus, What do you understand by term -...

What do you understand by term - acanthus The egg and larval phase of an acanthocephalan which passes from the female parasite to the feces of host.

Technical requirements for pulmonary angiography, Q. Technical Requirements...

Q. Technical Requirements for pulmonary angiography? Digital subtraction pulmonary angiography with selective pulmonary arterial injections is vastly superior to conventional c

How gender affects the bmr, How Gender affects the bmr? We have already...

How Gender affects the bmr? We have already emphasized earlier that sex difference in metabolic rates are primarily attributable to difference in body size and composition. Wom

What do you mean by proteinuria, Q. What is proteinuria? Why is proteinuria...

Q. What is proteinuria? Why is proteinuria a sign of glomerular renal injury? Proteinuria means losing of proteins through urine under normal conditions proteins are too big to

Write short note on cholesterol, Cholesterol, from stereos (solid) and the...

Cholesterol, from stereos (solid) and the Greek chole- (bile) followed by the chemical suffix -ol for an alcohol is an organic chemical substance classified as a waxy steroid of fa

Carbon cycle, state 3 ways human activities add carbon to the atmosphere

state 3 ways human activities add carbon to the atmosphere

Short-term and long-term effects of forest destruction, List the short-term...

List the short-term and long-term effects of forest destruction  (a) on hillsides, (b) in the tropics.  (a) Deforestation on hillsides exposes the soil to erosion by rain and l

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