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Mendel’s model system

Mendel’s seminal work was accomplished using the garden pea, Pisum sativum , to study inheritance. This species naturally self-fertilizes, such that pollen encounters ova within individual flowers. The flower petals remain sealed tightly until after pollination, preventing pollination from other plants. The result is highly inbred, or “true-breeding,” pea plants. These are plants that always produce offspring that look like the parent. By experimenting with true-breeding pea plants, Mendel avoided the appearance of unexpected traits in offspring that might occur if the plants were not true breeding. The garden pea also grows to maturity within one season, meaning that several generations could be evaluated over a relatively short time. Finally, large quantities of garden peas could be cultivated simultaneously, allowing Mendel to conclude that his results did not come about simply by chance.

Mendelian crosses

Mendel performed hybridizations , which involve mating two true-breeding individuals that have different traits. In the pea, which is naturally self-pollinating, this is done by manually transferring pollen from the anther of a mature pea plant of one variety to the stigma of a separate mature pea plant of the second variety. In plants, pollen carries the male gametes (sperm) to the stigma, a sticky organ that traps pollen and allows the sperm to move down the pistil to the female gametes (ova) below. To prevent the pea plant that was receiving pollen from self-fertilizing and confounding his results, Mendel painstakingly removed all of the anthers from the plant’s flowers before they had a chance to mature.

Plants used in first-generation crosses were called P 0    , or parental generation one, plants ( [link] ). Mendel collected the seeds belonging to the P 0 plants that resulted from each cross and grew them the following season. These offspring were called the F 1    , or the first filial ( filial = offspring, daughter or son), generation. Once Mendel examined the characteristics in the F 1 generation of plants, he allowed them to self-fertilize naturally. He then collected and grew the seeds from the F 1 plants to produce the F 2    , or second filial, generation. Mendel’s experiments extended beyond the F 2 generation to the F 3 and F 4 generations, and so on, but it was the ratio of characteristics in the P 0 −F 1 −F 2 generations that were the most intriguing and became the basis for Mendel’s postulates.

The diagram shows a cross between pea plants that are true-breeding for purple flower color and plants true-breeding for white flower color. This cross-fertilization of the P generation resulted in an F_{1} generation with all violet flowers. Self-fertilization of the F_{1} generation resulted in an F_{2} generation that consisted of 705 plants with violet flowers, and 224 plants with white flowers.
In one of his experiments on inheritance patterns, Mendel crossed plants that were true-breeding for violet flower color with plants true-breeding for white flower color (the P generation). The resulting hybrids in the F 1 generation all had violet flowers. In the F 2 generation, approximately three quarters of the plants had violet flowers, and one quarter had white flowers.

Garden pea characteristics revealed the basics of heredity

In his 1865 publication, Mendel reported the results of his crosses involving seven different characteristics, each with two contrasting traits. A trait    is defined as a variation in the physical appearance of a heritable characteristic. The characteristics included plant height, seed texture, seed color, flower color, pea pod size, pea pod color, and flower position. For the characteristic of flower color, for example, the two contrasting traits were white versus violet. To fully examine each characteristic, Mendel generated large numbers of F 1 and F 2 plants, reporting results from 19,959 F 2 plants alone. His findings were consistent.

Questions & Answers

what is science?
Benedict Reply
Science is the method of acquiring skills and knowledge through experimentation and observation in the World Series
Richmond
where does meiosis occur in male plant reproductive organ
Gimai Reply
plant cell is plasmolysed as a result of the
Favour Reply
of the plant losing water
Esnart
"Head of a pin" means what?
Theresah Reply
types of genotype and types of blood group
Adebusuyi Reply
what is biology
Musa Reply
is the study of cell and structure of an organism
Atem
is the study of characteristics,life processes and phenomana of living organism
Atem
What is Monomer of protein?
Dimpho Reply
What's nutrition and types of nutrition
Jessica Reply
Why is cheetah d fastest animal
Jessica Reply
because they are capable of reaching speeds of up to 70mph
Abu
Thanks
Jessica
what is a cell
Reuben Reply
what is an enzymes
Reuben
a cell is a biological catalyst that speeds up the rate of a chemical reaction without itself been changed
Israel
a cell is smallest unit of life
Francis
an Enzyme helps speed up a chemical reaction
Francis
is the basic structural and functional unit of all organism
Atem
what is deamination
Mutebi Reply
Is the removal of amino radical from amino acid or any other amino compound.
Esnart
what is metabolism
Allen Reply
metabolism is the the combination of all the reaction that occur within your body
xjuicy_editzz
These reaction can be either anabolic (which is the building up of molecules) or can be catabolism (breaking of molecules) but these processes occur simultaneously to maintain homeostasis(internal body environment) within the body.
xjuicy_editzz
hope that helps :D !!
xjuicy_editzz
list 20 element in their order
Dor Reply
hydrogen helium lithium beryllium boron carbon nitrogen oxygen fluorine neon sodium Magnesium aluminium silicon phosphorus sulfur chlorine Aaron potassium calcium -Also if anyone is having trouble remembering the elements I recommend watching "The Periodic Table of elements song" :)
xjuicy_editzz
anabolic, Because ATP is needed
Avuyileji Reply
?
xjuicy_editzz
definition of biology
LENARD Reply
the branch of science that deals with the study of plants and animals
Emmanuel

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Source:  OpenStax, Biology. OpenStax CNX. Feb 29, 2016 Download for free at http://cnx.org/content/col11448/1.10
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