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he·red·i·ty
Noun
(hə red’ ə tē)
•The genetic transmission of
characteristics from parent to
offspring.
•One's genetic constitution.
•The sum of the qualities and
potentialities genetically derived from
one's ancestors
•The passing of traits from parents
to offspring
gene
Noun
(jēn)
A portion of a DNA molecule that
serves as the basic unit of heredity.
Genes control the characteristics
that an offspring will have by
transmitting information in the
sequence of nucleotides on short
sections of DNA.
Segments of DNA that carry
hereditary instructions and are passed
from parent to offspring: located in
chromosomes.
Traits
a distinguishing
quality that can
be passed from
one generation
to another
dominant trait
adjective
noun
(Däm’ə nənt trāt)
In genetics, a trait that will appear in
the offspring if one of the parents
contributes it.
Example: In humans, dark hair is a
dominant trait; if one parent
contributes a gene for dark hair and
the other contributes a gene for light
hair, the child will have dark hair.
The trait observed when at least one
dominant allele for a characteristic is
inherited
recessive trait
adjective
noun
(ri ses’iv trāt)
In genetics, a trait that must be contributed by
both parents in order to appear in the offspring.
Recessive traits can be carried in a person’s
genes without appearing in that person.
For example, a dark-haired person may have one
gene for dark hair, which is a dominant trait, and
one gene for light hair, which is recessive. It is
thus possible for two dark-haired parents to have
a light-haired child, provided each parent
contributes a gene for light hair.
A trait that is apparent only when two recessive
alleles for the same characteristic are inherited
alleles
noun
(ə lēl’)
The different forms of a gene. Y and
y are different alleles of the gene that
determines seed color. Alleles
occupy the same locus, or position,
on chromosomes.
Different forms of a single gene
genotype
noun
(jen’ə tīp)
The genetic constitution of an
organism with respect to a trait. For
a single trait on an autosome, an
individual can be homozygous for
the dominant trait, heterozygous, or
homozygous for the recessive trait.
Yellow seeds are dominant, but
yellow seeded plants could have a
genotype of either YY or Yy.
The inherited combination of
alleles
homozygous
adjective
(hō-mŏ-zīgəs)
Both alleles for a trait are
the same in an
individual. They can be
homozygous dominant
(YY), or homozygous
recessive (yy).
heterozygous
adjective
(hĕt ə-rō-zīgəs)
Differing alleles for a
trait in an individual,
such as Yy.
phenotype
noun
(fē’nə-tīp’)
The physical appearance of an
organism with respect to a trait, i.e.
yellow (Y) or green (y) seeds in
garden peas. The dominant trait is
normally represented with a capital
letter, and the recessive trait with
the same lower case letter.
An organism’s inherited
appearance
Incomplete
dominance
sometimes a trait is not
completely dominant
over another, however
these traits do not
blend, but each allele
has its own degree of
influence
Inherit
to receive
characteristics from
parents
Probability
the
mathematical
chance that an
event will occur