Chapter 15 Flashcards
Loci
Position
What is the Chromosome Theory of Inheritance
Mendelian genes have specific loci (position) on chromosomes
Chromosomes undergo segregation and independent assortment
Wild type
Normal
Why use fruit flies?
Breed at high rates
Generations can be bred every two weeks
Only one pair of chromosomes
XX
Female
XY
Male
Sex-linked gene
Gene located on either sex chromosome
In humans, sex-linked usually refers to a gene on…
The larger X chromosome
In order for recessive sex-linked traits to be expressed..
A female needs…
A male needs…
A female needs two copies of the allele
A male needs only one copy of the allele
Sex-linked recessive disorders are common in
Males
What is a Barr body?
What the inactive X condenses into
Disorders caused by recessive alleles on the X chromosome are..
Color blindness
Duchenne muscular dystrophy
Hemophilia
A female will be a mosaic for a character if…
She is heterozygous for a gene located on the X chromosomes
What are linked genes?
Genes located on the same chromosome that tend to be inherited together
What is genetic recombination?
The production of offspring with combinations of traits differing from either parent
What are parental types?
Offspring with phenotypes matching one of the parental phenotypes
What are recombinant?
Offspring with nonparental phenotypes
New combination of traits
Crossing over
The breaking of the physical connection between genes on the same chromosome
Nondisjunction
Pair of homologous chromosomes do not separate normally during meiosis
Result of nondisjunction
One gamete receives 2 of the same type of chromosome
The other receives no copy
Aneuploidy results from…?
The fertilization of gametes in which nondisjunction occurred
Offspring with Aneuploidy…
Have abnormal number of a particular chromosome
Monosomic Zygote
Has only one copy of a particular chromosome
Trisomic Zygote
Has three copies of a particular chromosomes
Polyploidy
A condition in which an organism has more than 2 complete sets of chromosome
Triploidy
3n
Three sets of chromosome
Tetraploidy
4n
4 sets of chromosomes
Alternation of Chromosome structure can happen by way of….
Deletion
Duplication
Inversion
Translocation
Deletion…
Removes a chromosomal segment
ABCDE —–> ABCE
Duplication…
Repeats a segment
Inversion…
Reverses a segment within a chromosome
Translocation…
Moves a segment from one chromosome to another
