Chapter 20 Pt. 2 Flashcards
What is a pedigree?
a chart showing the genetic connections between individuals in a family
_________ ___________-inheritance of genetic
autosomal dominant
_________ __________-genetic disorders caused by recessive alleles on a pair of non-sex chromosomes
autosomal recessive
Which type of dominance is this:
a situation in which a heterozygous individual exhibits the trait associated with the dominant allele but not that of the recessive allele
complete dominance
Which type of dominance is this:
the expression of a trait in a heterozygous individual is somewhere between the expression of the trait in a homozygous dominant individual and the expression of the trait in a homozygous recessive individual
incomplete dominance
Which type of dominance is this:
The inheritance of type AB blood
codominance
Which type of dominance is this:
sickle-cell anemia
incomplete dominance
What is pleiotropy?
one gene leading to many effects
_______ _______- when 3 or more forms of a given gene exist
multiple alleles
What is polygenic inheritance?
the involvement of 2 or more genes, often on different chromosomes, in predicting a trait
the more genes involved, the smoother the _________ and the greater the extremes of _____ _________
gradations
trait expression
Genes that tend to be inherited together are described as being ______
linked
True or False: Linked genes usually tend to assort independently
False; Linked genes usually don’t assort independently
__-______ ______-most genes on the X chromosome have no corresponding alleles on the Y chromosome
X-linked genes
the recessive phenotype of X-linked genes is much more common in which sex?
males
True or False: a son cannot inherit an X-linked recessive allele from his father
True
True or False: a daughter, cannot inherit an X-linked recessive alley from either parent
False; a daughter can inherit an X-linked recessive alley from either parent
What are the disorders caused by X-linked recessive alleles?
red-green color blindness
two forms of hemophilia
Duchenne muscular dystrophy
What is the cause of breakage among chromosomes?
certain chemicals, radiation, or viruses
What is the difference between deletion and duplication?
deletion-the loss of a piece of chromosome
duplication- the addition of a piece of chromosome
What is the most common type of deletion?
occurs when the tip of a chromosome breaks off and then, during cell division, doesn’t move into the same daughter cell as the rest of the chromosome
What happens when you delete more than a few genes on an autosome?
is usually lethal
The loss of small regions, due to deletion, can cause ________
disorders
Cri-du-chat syndrome is an example of _______
deletion
___-__-___ ________ is an example of deletion
Cri-du-chat syndrome
What is Cri-du-chat syndrome?
“cry of the cat”; caused by the loss of a small region near the tip of chromosome 5
What is Fragile X Syndrome?
an abnormally long sequence of repeats caused by duplication makes the X chromosome fragile and easily broken
_______ __ ________ is an example of duplication
Fragile X Syndrome
Fragile X Syndrome is an example of _________
duplication
______ __ ________ is the most common form of inherited mental impairment
Fragile X Syndrome
True or False: a small deletion is less harmful than a duplication of comparable size
False; a small duplication is less harmful than a deletion of comparable size
What are the two procedures available for diagnosing genetic problems in the fetus?
(1) amniocentesis
2) chorionic villi sampling (CVS
____________- a needle is inserted through the lower abdomen into the uterus, and a small amount of amniotic fluid is withdrawn
amniocentesis
________ ____ ________ (____)- removes and analyzes a small amount of tissue containing chorionic villi, the small, fingerlike projections of the part of the placenta called the chorion
chorionic villi sampling (CVS)
