TOPIC 2 - Genetic Foundations of Development Flashcards
is not just inherited from our parents; it includes what we inherited as a species from other species that were our ancestors.
DNA
evolved over time and across many species.
Genetic influences on behavior
Each of us carries a “____” that we inherited from our parents.
genetic code
Each of us began life as a single cell weighing about ____
one twenty-millionth of an ounce
which are threadlike structures made up of deoxyribonucleic acid (DNA).
chromosomes
is a complex molecule that has a double helix shape, like a spiral staircase and contains genetic information
DNA
the units of hereditary information, are short segments of DNA.
Genes
They help cells to reproduce themselves and to assemble proteins.
Genes
are the building blocks of cells as well as the regulators that direct the body’s processes
Proteins
Among the major approaches to gene identification and discovery that are being used today are the
genome-wide association method
linkage analysis
next-generation sequencing
Thousand Genomes Project
to identify genetic variations linked to a particular disease, such as obesity, cancer, cardiovascular disease, or Alzheimer disease
genome-wide association method
researchers obtain DNA from individuals who have the disease and others who don’t have it. Then, each participant’s complete set of DNA, or genome, is purified from the blood or other cells and scanned on machines to determine markers of genetic variation. If the genetic variations occur more frequently in people who have the disease, the variations point to the region in the human genome with the disease.
genome-wide association
in which the goal is to discover the location of a gene (or genes) in relation to a marker gene (whose position is already known
Linkage analysis
is often used to search for disease- related genes
Linkage analysis
is a term used to describe the vast increase in genetic data generated at a much reduced cost and in a much shorter period of time than in the past.
Next-generation sequencing
A current project that began in 2008
Thousand Genomes Project
is the most detailed study of human genetic variation to date. This project has the goal of determining the genomic sequences of at least 1,000 individuals from different ethnic groups around the world (Li & others, 2017)
Thousand Genomes Project
A gene does not act _____. Rather than being a group of independent genes
independently
consists of many genes that collaborate both with each other and with nongenetic factors inside and outside the body
human genome
The activity of genes (genetic expression) is affected by their ____
environment
that certain genes become turned on or off as a result of exercise mainly through a process called
methylation
This process makes the gene more or less capable of receiving and responding to biochemical signals from the body
methylation
the cell’s nucleus-including the chromosomes-duplicates itself and the cell divides. Two new cells are formed, each containing the same DNA as the original cell, arranged in the same 23 pairs of chromosomes.
Mitosis
a cell of the testes (in men) or ovaries (in women) duplicates its chromosomes but then divides twice, thus forming four cells, each of which has only half of the genetic material of the parent cell. By the end of meiosis, each egg or sperm has 23 unpaired chromosomes.
Meiosis
an egg and a sperm fuse to create a single cell called a zygote
Fertilization
the 23 unpaired chromosomes from the egg and the 23 unpaired chromosomes from the sperm combine to form one set of 23 paired chromosomes-one chromosome of each pair coming from the mother’s egg and the other from the father’s sperm.
Zygote
those that make the individual more vulnerable to specific diseases or accelerated aging
susceptibility genes
those that make the individual less vulnerable to certain diseases and more likely to live to an older age
longevity genes
mistake by cellular machinery, or damage from an environmental agent such as radiation may produce a _____, which is a permanently altered segment of DNA
mutated gene
one gene of a pair always exerts its effects; it is dominant and overrides the potential influence of the other gene, called the recessive gene.
dominant- recessive genes principle.
Most mutated genes are ___.
recessive
When a mutated gene is carried on the X chromosome, the result is called
X-linked inheritance
examples of X-linked inheritance diseases
Hemophilia
Fragile X
Remember that males have only ___ X chromosome.
one
if there is an absent or altered disease-relevant gene on the X chromosome, males have no “backup” copy to counter the harmful gene and therefore may develop an _____
X-linked disease.
Remember that ____ have only one X chromosome.
males
have a second X chromosome, which is likely to be unchanged.
females
Females who have one abnormal copy of the gene on the X chromosome are known as ___
carriers
Brown hair, farsightedness, and dimples are
dominant genes
blond hair, nearsightedness, and freckles
recessive genes.
Is a bleeding disorder where blood doesn’t clot properly due to a deficiency in certain clotting factors
Hemophilia
genetic disorder caused by changes in the FMR1 gene, located on the X chromosome
Fragile x syndrome
occurs when the expression of a gene has different effects depending on whether the mother or the father passed on the gene
Genetic imprinting
A chemical process “silences” one member of the gene pair.
Genetic imprinting
(a growth disorder)
Beckwith-Wiedemann syndrome
(a type of cancer)
Wilms tumor
is usually more complex than the simple examples we have examined thus far
Genetic transmission
means that many different genes determine a characteristic
polygenic inheritance
is increasingly used to describe studies that focus on the interdependent process by which two or more genes influence characteristics, behavior, diseases, and development
gene-gene interaction
Sometimes a gamete is formed in which the male’s sperm and/or the female’s ovum do not have their normal set of 23 chromosomes.
Chromosomal Abnormalities
form of intellectual disability caused by the presence of an extra copy of chromosome 21
Down syndrome
has a round face, a flattened skull, an extra fold of skin over the eyelids, a protruding tongue, short limbs, and impaired motor and mental abilities.
Down syndrome
involve the presence of an extra chromosome (either an X or Y) or the absence of one X chromosome in females.
Sex-Linked Chromosomal Abnormalities
is a chromosomal disorder in which males have an extra X chromosome, making them XXY instead of XY
Klinefelter syndrome
is a chromosomal disorder in females in which either an X chromosome is missing, making the person XO instead of XX, or part of one X chromosome is deleted
Turner syndrome
Females with Turner syndrome are _____
short in stature and have a webbed neck
is a genetic disorder that results from an abnormality in the X chromosome, which becomes constricted and often breaks
Fragile X syndrome (FXS)
is a chromosomal disorder in which a male has an extra Y chromosome
XYY syndrome
a learning disability, or a short attention span
autism
Abnormalities can be produced not only by an abnormal number of chromosomes but also by harmful genes.
Gene-Linked Abnormalities
More than _____ such genetic disorders have been identified, although most of them are rare
7,000
Two widely studied gene-linked abnormalities are
phenylketonuria
sickle-cell anemia.
is a genetic disorder in which the individual cannot properly metabolize phenylalanine, an amino acid. It results from a recessive gene and occurs about once in every 10,000 to 20,000 live births.
Phenylketonuria (PKU)
which occurs most often in African Americans, is a genetic disorder that impairs the functioning of the body’s red blood cells.
Sickle-cell anemia
a recessive gene causes the red blood cell to become a hook- shaped “sickle” that cannot carry oxygen properly and dies quickly
Sickle-cell anemia
Red blood cells carry oxygen to the body’s other cells and are usually _____.
disk-shaped
Recent research strongly supports the use of _____ for infants with sickle cell anemia, beginning at 9 months of age
hydroxyurea therapy
one gene of a pair always exerts its effects;
Dominant genes
overrides the potential influence of the other gene
Recessive genes
When imprinting goes awry, development is disturbed
Beckwith-Wiedeman Syndrome
Glandular dysfunction that interferes with mucus production; breathing and digestion are hampered, resulting in a shortened life span.
Cystic fibrosis
Body does not produce enough insulin, which causes abnormal metabolism of sugar.
Diabetes
Central nervous system deteriorates, producing problems in muscle coordination and mental deterioration
Huntington disease
Neural tube disorder that causes brain and spine abnormalities
Spina bifida
Deceleration of mental and physical development caused by an accumulation of lipids in the nervous system.
Tay-Sachs disease
