Chapter 14
Concept 14.1
Mendel (scientist) discovered the basic principles of heredity by breeding garden
peas in carefully planned experiments.
A heritable feature that varies among individuals, such as flower color, is called
character.
Each variant of for a character, such as purple or white color for flowers, is called
a trait.
Mendel removed the immature stamens of a plant before they produced pollen
and then dusted pollen from another plant onto the altered flowers. Each
resulting zygote then developed into a plant embryo encased in a seed (pea).
Mendel could thus always be sure of the parentage of new seeds.
True-breeding Produced only the same variety as the parent plant. An
example: a plant with purple flowers is true-breeding if the seeds produced by
self-pollination in successive generations all give rise to plants that also have
purple flowers.
Hybridization crossing two true-breeding varieties. An example: crossing two
true-breeding varieties such as a white-flowered plants and a purple-flowered
plants.
The true-breeding parents are referred to as the P generation and their hybrid
offspring are F1generation. If the F1generation gets hybrids, that are the
F2generation etc.
With the F1 and F2 generation, you can see the results of the colors. The colors of
the generations shows which color is a dominant trait, or a recessive trait.
Alternative versions of genes account for variations in inherited characters. The
gene for flower colors in pea plants etc. These alternative versions of a gene are
called alleles. This can be related to chromosomes and DNA. This variation in
information content can affect the function of the encoded protein and thus the
phenotype of the organisms.
For each character, an organism inherits two copies (two alleles) of a gene, one
from each parent. Each somatic cell in a diploid organism had two sets of
chromosomes, one set inherited from each parent. Thus, a genetic locus is
actually represented twice in a diploid cell, once on each homolog of a specific
pair of chromosomes.
If the two alleles at a locus differ, then one, the dominant allele, determines
the organism’s appearance; the other; the recessive allele, has no noticeable
effect on the organism’s appearance.
The law of segregation the two alleles for a heritable character segregate
(separate from each other) during gamete formation and end up in different
gametes. Thus, an egg or a sperm get only one of the two alleles that are present
in the somatic cells of organism making the gamete. In terms of chromosomes,
Concept 14.1
Mendel (scientist) discovered the basic principles of heredity by breeding garden
peas in carefully planned experiments.
A heritable feature that varies among individuals, such as flower color, is called
character.
Each variant of for a character, such as purple or white color for flowers, is called
a trait.
Mendel removed the immature stamens of a plant before they produced pollen
and then dusted pollen from another plant onto the altered flowers. Each
resulting zygote then developed into a plant embryo encased in a seed (pea).
Mendel could thus always be sure of the parentage of new seeds.
True-breeding Produced only the same variety as the parent plant. An
example: a plant with purple flowers is true-breeding if the seeds produced by
self-pollination in successive generations all give rise to plants that also have
purple flowers.
Hybridization crossing two true-breeding varieties. An example: crossing two
true-breeding varieties such as a white-flowered plants and a purple-flowered
plants.
The true-breeding parents are referred to as the P generation and their hybrid
offspring are F1generation. If the F1generation gets hybrids, that are the
F2generation etc.
With the F1 and F2 generation, you can see the results of the colors. The colors of
the generations shows which color is a dominant trait, or a recessive trait.
Alternative versions of genes account for variations in inherited characters. The
gene for flower colors in pea plants etc. These alternative versions of a gene are
called alleles. This can be related to chromosomes and DNA. This variation in
information content can affect the function of the encoded protein and thus the
phenotype of the organisms.
For each character, an organism inherits two copies (two alleles) of a gene, one
from each parent. Each somatic cell in a diploid organism had two sets of
chromosomes, one set inherited from each parent. Thus, a genetic locus is
actually represented twice in a diploid cell, once on each homolog of a specific
pair of chromosomes.
If the two alleles at a locus differ, then one, the dominant allele, determines
the organism’s appearance; the other; the recessive allele, has no noticeable
effect on the organism’s appearance.
The law of segregation the two alleles for a heritable character segregate
(separate from each other) during gamete formation and end up in different
gametes. Thus, an egg or a sperm get only one of the two alleles that are present
in the somatic cells of organism making the gamete. In terms of chromosomes,
