Chapter 16: Human Genetics and the Human Genome

Sickle cell anemia

________ is an autosomal recessive disorder in which abnormal hemoglobin (the protein that transports oxygen in the blood) is produced.

Hemophilia

________ is an X- linked recessive disorder that results in a defect in a blood component required for clotting.

Trisomy

________ and monosomy are caused by meiotic nondisjunction, in which sister chromatids or homologous chromosomes fail to move apart properly during meiosis.

CVS

________ provides results in the first trimester of pregnancy but is associated with a slightly greater risk of infection and miscarriage than amniocentesis.

PGD

________ is not as accurate as amniocentesis or CVS, and it is more expensive.

Cystic fibrosis

________ is an auto- somal recessive disorder in which abnormal secretions are produced primarily in organs of the respiratory and digestive systems.

Deletion

A(n) ________ can result in chromosome breaks that fail to rejoin.

Aneuploidy

In ________ there are either missing or extra copies of certain chromosomes.

Phenylketonuria

________ is an autosomal recessive disorder in which toxic phenylketones damage the developing nervous system.

Genomic imprinting

________ can affect the expression of a gene based on its parental origin.

E coli

The identification of genes and genomic regions in other species that are highly conserved with those in humans allows investigators to study their structure and function in model organisms such as the mouse, Drosophila, C. elegans, yeast and ________.

Amniocentesis

________ provides results in the second trimester of pregnancy.

Tay Sachs disease

________ is an autosomal recessive disorder caused by abnormal lipid metabolism in the brain.

Huntingtons disease

________ has an autosomal dominant inheritance pattern and results in mental and physical deterioration, usually beginning in adulthood.

Fragile sites

________ may occur at specific locations on both chromatids of a chromosome.

Pedigree analysis

________ is useful in detecting autosomal dominant mutations, autosomal recessive mutations, X- linked recessive mutations, and defects due to genomic imprinting, which is the expression of a gene based on its parental origin.

Pedigree

A(n) ________ is a "family tree "that shows the transmission of genetic traits within a family over several generations.

normal allele

In gene therapy the ________ is cloned, and the DNA is introduced into certain human cells where its expression may be sufficient to yield a normal phenotype.

Amniocentesis

In ________ a physician samples the amniotic fluid surrounding the fetus and then cultures and screens the fetal cells suspended in the fluid for genetic defects.

Cystic fibrosis is an auto

somal recessive disorder in which abnormal secretions are produced primarily in organs of the respiratory and digestive systems