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

Gonad glands, what are the gonad gland disorders and what do they do

what are the gonad gland disorders and what do they do

Coadapted communities, From your studies in ecology, you must be aware that...

From your studies in ecology, you must be aware that most ecosystems are quite complex consisting of several habitats and that habitats in turn are composed of microhabitats. Each

Describe metabolism, Q What is metabolism? Metabolism is the set of che...

Q What is metabolism? Metabolism is the set of chemical and physical processes upon which the life of the cells of a living being depends.

Epiboly of ectoderm, Epiboly of Ectoderm Like the presumptive endoder...

Epiboly of Ectoderm Like the presumptive endodermal notochordal and mesodermal cells migrate inward the areas in the epiblast vacated through them are occupied by expansion (

Reproduction, The fusion of two individuals with each acting as a gamete is...

The fusion of two individuals with each acting as a gamete is known as

Cation saturation and nutrient absorption by plants, Cation Saturation and ...

Cation Saturation and Nutrient Absorption by Plants The availability of adsorbed cations is not always so easy as the above explanation might suggest. This is because, several

Modern biochemistry and cell physiology, This problem set is a little diffe...

This problem set is a little different, in that it is one large project/problem. To answer it, you must write a short single-spaced typed report of 4-5 pages MAXIMUM. Here is the p

Parasternal position, Examination is begun by placing the transducer in l...

Examination is begun by placing the transducer in left parasternal region, usually in the third or fourth left intercostal space. From this position, a sector image of the heart

VASCULAR PLANTS., WHAT TRAITS ALLOWED VASCULAR PLANTS TO GROW TALL

WHAT TRAITS ALLOWED VASCULAR PLANTS TO GROW TALL

Explain non-nucleoside reverse transcriptase inhibitors, Non-nucleoside rev...

Non-nucleoside reverse transcriptase inhibitors (NNRTIs) - These drugs are direct, non-nucleoside inhibitors of HIV-1 reverse transcriptase. Combinations of an NNRTI with NRTIs

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