Chapter 15: Flashcards
What stage of meiosis is responsible for independent assortment?
metaphase I
What stage of meiosis is responsible for segregation of alleles?
Anaphase I
What is the phenotype most commonly observed for a character referred to as?
The wild type
T or F? Any male receiving a recessive gene from his mother will have the trait?
T
What is the term used for males instead of homozygous and heterozygous?
hemizygous
What are two examples of X-linked recessive diseases given in the book?
Color blindness
Duchenne Muscular Dystrophy
What is a Barr body?
The inactive form of and X chromosome
What is the gene activated on Barr body chromosomes?
XIST
What are linked genes?
genes that due to their position on a chromosome tend to be inherited together
What is genetic recombination?
the production of offspring with combinations of traits that differ from their parents
Offspring that take on the characteristics of one of their parents are known as?
Parental types
What is the physical basis of recombination between unlinked genes?
random orientation of homologous chromosomes at metaphase I of meiosis
Offspring will only differ from the phenotypes of their parents in what occurs?
crossing over
What is a genetic map?
An ordered list of genetic loci along a chromosomes
What is a linkage map?
A genetic map based on recombinant frequencies
What are map units?
1% recombinant frecuencias
What is non disjunction?
When homologous pairs fails to move apart during meiosis I or sister chromatids fall to separate during meiosis II
What are the results of non dis junction?
One game receives 2 chromosomes and one receives none
When a zygote has an abnormal number of a particular chromosome the condition is known as what?
Aneuploidy
When a cell is missing a chromosome (2n-1) it is known as
monosomic
When a cell has an extra chromosome (2n + 1) it is known as
trisomic
Down syndrome is a form of (monosomy/trisomy)?
trisomy
What are the 4 types of changes that can occur in a chromosome structure?
deletion
duplication
inversion
translocation
What is deletion?
chromosomal fragment lost