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

Planning and implementation of nursing care - anaemia, Planning of Nursing ...

Planning of Nursing Care   The goals of nursing care are:  Administer oral iron supplements and parenteral iron therapy.  Provide nutritional counselling and educate t

Digestive system, steps of digestive system in amoeba,with a clear picture ...

steps of digestive system in amoeba,with a clear picture description

Explain the phylum molluska - mollusks, Explain the Phylum Molluska - Mollu...

Explain the Phylum Molluska - Mollusks? You are probably very familiar with members of this phylum. The mollusks include the octopuses, squids, cuttlefish, scallops, oysters, c

Explain about nutritional recommendations for healthy ageing, Explain about...

Explain about the Nutritional recommendations for Healthy Ageing? You would recall reading about meal planning during various stages of life, spanning right from the infancy ti

Mode of hormone action through extracellular receptors, MOD E OF HORMONE A...

MOD E OF HORMONE ACTION THROUGH EXTRACELLULAR RECEPTORS - The molecules of amino acid derivatives, peptides or polypeptide (protein) hormones bind to specific receptor molecul

Determine the estimation of minerals in foods, Estimation of minerals in fo...

Estimation of minerals in foods The minerals in foods are determined by ashing or incineration at temperatures in the region of 500°C following standard procedure. This destroy

Prokaryotes and eukaryotes, Prokaryotes and Eukaryotes By now, you kno...

Prokaryotes and Eukaryotes By now, you know that cell theory holds good for all living forms. However, if you examine under the microscope, the cells of a bacterium, a blue gr

What er the parafunctional habits, What er the Parafunctional Habits P...

What er the Parafunctional Habits Parafunctional Habits like bruxism and clenching create mechanical and biological problems due to overloading and are considered to be one of

Why is the cytoplasm of sperm cells very reduced, Why is the cytoplasm of s...

Why is the cytoplasm of sperm cells very reduced? Why do mitochondria of sperm cells concentrate in the base of the flagellum ? The decreased cytoplasm of sperm cells reduces th

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