Biology Chapter 9 Vocab Flashcards
Allele
An alternative version of a gene.
Carrier
An individual who is heterozygous for a recessively inherited
disorder and who therefore does not show symptoms of that disorder
but who may pass on the recessive allele to offspring.
Character
A heritable feature that varies among individuals within a
population, such as flower color in pea plants or eye color in humans.
Dihybrid Cross
An experimental mating of individuals
that are each heterozygous for both of two characters (or the self-pollination
of a plant that is heterozygous for both characters).
Dominant Allele
The allele that determines the phenotype
of a gene when the individual is heterozygous for that gene.
F1 generation
The offspring of two parental (P generation) individuals;
F1 stands for first filial.
F2 Generation
The offspring of the F1 generation; F2 stands for second
filial.
Genotype
The genetic makeup of an organism.
Heredity
The transmission of traits (inherited features) from one generation
to the next.
Heterozygous
Having two different alleles for a
given gene.
Homozygous
Having two identical alleles for a given
gene.
Hybrid
Offspring that results from the mating of individuals from
two different species or from two true-breeding varieties of the same
species; an offspring of two parents that differ in one or more inherited
traits; an individual that is heterozygous for one or more pairs
of genes.
Law of Independent Assortment
A general rule of inheritance (originally
formulated by Gregor Mendel) that when gametes form during
meiosis, each pair of alleles for a particular character segregates
independently of other pairs; also known as Mendel’s second law of
inheritance.
Law of Segregation
A general rule in inheritance (originally formulated
by Gregor Mendel) that individuals have two alleles for each
gene and that when gametes form by meiosis, the two alleles separate,
each resulting gamete ending up with only one allele of each gene;
also known as Mendel’s first law of inheritance.
Linked Genes
Genes located near each other on the same chromosome
that tend to be inherited together.
Locus
The particular site where a gene is found on a chromosome.
Homologous chromosomes have corresponding gene loci
Monohybrid Cross
An experimental mating of individuals that are
heterozygous for the character being followed (or the self-pollination
of a heterozygous plant).
Mutant
The version of a character that occurs less frequently in nature
than the wild-type
P Generation
The parent individuals from which offspring are derived
in studies of inheritance; P stands for parental
Phenotype
The expressed traits of an organism.
Polygenic Inheritance
The additive effects of two or
more gene loci on a single phenotypic character.
Recessive Allele
An allele that has no noticeable effect on the phenotype
of a gene when the individual is heterozygous for that gene.
Sex Chromosome
A chromosome that determines whether an individual
is male or female.
Sex-linked Gene
A gene located on a sex chromosome. In humans, the
vast majority of sex-linked genes are located on the X chromosome
Testcross
The mating between an individual of unknown genotype for a particular character and an individual that is homozygous recessive for that same character. The testcross can be used to determine the unknown genotype (homozygous dominant versus heterozygous).
Trait
A variant of a character found within a population, such as purple
or white flowers in pea plants.
True-breeding
Referring to organisms for which sexual reproduction
produces offspring with inherited traits identical to those of the
parents. The organisms are homozygous for the characters under
consideration.
Wild-type
The version of a character that most commonly occurs in
nature.
