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

O-linked oligosaccharides , Most proteins made by ribosomes on the RER (rou...

Most proteins made by ribosomes on the RER (rough endoplasmic reticulum) are glycoproteins, which is they hold short chains of carbohydrates (oligosaccharides) covalently related t

General biology , What organic molecules make up the cell membrane?

What organic molecules make up the cell membrane?

Explain cell membrane and plasma membrane, Explain cell membrane? The...

Explain cell membrane? The Cell Membrane :  The cell membrane, or plasma membrane, separates the cell from neighboring cells or from the external environment. Both prokaryot

The immediate effects of exercise on the heart and the lungs, (a) What are ...

(a) What are the immediate effects of exercise on the functions of (i) the heart, (ii) the lungs, (iii) the liver? (b) How do these changes help to meet the needs of exercise

Explain about the niacin - water soluble vitamin, Explain about the Niacin ...

Explain about the Niacin - Water Soluble Vitamin? Niacin is chemically synonymous with nicotinic acid although the term is also used for its amide (nicotinamide). Nicotinamide

Culture-negative endocarditis, Special studies to diagnose IE caused by fas...

Special studies to diagnose IE caused by fastidious bacteria and other organisms must be performed (serological studies). Thereafter, unless clinical or epidemiologic clues suggest

Chloroplasts, CHLOROPLASTS Schimper (1883) coined the term chlorop...

CHLOROPLASTS Schimper (1883) coined the term chloroplastid for green plastids. Mayer called them Autoplast. Chloroplast name proposed by Erera. Green plastids wi

Photosynthesis, test to prove that carbondioxide is needed for photosynthes...

test to prove that carbondioxide is needed for photosynthesis to take place

Short-day plants (sdp) - plant responses to light-dark cycle, Short-Day Pla...

Short-Day Plants (SDP) - Plant Responses to Light-Dark Cycles These plants only flower or flower more profusely and rapidly when given less than a certain (critical) number of

Asexual reproduction, Which type of asexual reproduction takes place in mon...

Which type of asexual reproduction takes place in monocystis?

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