Genes & Environment Flashcards
The genetic endowment that members of a particular species have in common; a contributor to universal species traits and patterns of maturation.
species heredity
The evolutionary principle that individuals who have characteristics advantageous for survival in a particular environment are most likely to survive and reproduce. Over many generations, this process of “survival of the fittest” will lead to changes in a species and the development of new species.
natural selection
Change in a species achieved not through biological evolution but through learning and passing on from one generation to the next new ways of adapting to the environment.
cultural evolution
The moment of fertilization, when a sperm penetrates an ovum, forming a zygote.
conception
A single cell formed at conception from the union of a sperm and an ovum.
zygote
A threadlike structure made up of genes; in humans, there are ?
chromosome
46 in the nucleus of each cell
The process in which a germ cell divides, producing sperm or ova; in humans, the products of meiosis normally contain ?.
meiosis
23 chromosomes
The process in which a cell duplicates its chromosomes and then divides into two genetically
identical daughter cells.
mitosis
Molecule whose chemical code makes up chromosomes and serves as our genetic endowment; it is made up of sequences of the chemicals ?
DNA Deoxyribonucleic acid
A (adenine), C (cytosine), G (guanine), and
T (thymine).
One of the possible variants of a particular gene.
allele
A massive, government-sponsored effort to decipher
the human genetic code.
Human Genome Project
A process in which genetic material is exchanged between pairs of chromosomes during meiosis.
crossing over
A chromosomal portrait created by staining chromosomes, photographing them under a high-power microscope, and arranging them into a predetermined pattern.
karyotype
The genetic endowment that an individual inherits.
genotype
The way in which a person’s genotype is expressed in observable or measurable characteristics.
phenotype
The activation of particular genes in particular cells of the body at particular times in life.
gene expression
The genetic mechanism through which a characteristic is influenced by only one pair of genes, one gene from the mother and its partner from the father.
single gene-pair inheritance
A condition in which a stronger gene fails to mask all the effects of a weaker partner gene; a phenotype results that is similar but not identical to the effect of the stronger gene.
incomplete dominance
In genetics, an instance in which two different but equally powerful genes produce a phenotype in which both genes are expressed.
codominance
An attribute determined by a gene that appears on one of the two types of sex chromosomes, usually the X chromosome.
sex-linked characteristic
A deficiency in the blood’s ability to clot. It is more common among males than females because it is associated with a sex-linked gene on the X chromosome.
hemophilia
A characteristic influenced by the action of many gene pairs rather than a single pair.
polygenic trait
A change in the structure or arrangement of one or more genes that produces a new phenotype.
mutation
A genetic blood disease in which red blood cells assume an unusual sickle shape and become inefficient at distributing oxygen throughout the body.
sickle-cell disease
Conditions in which a child has too few, too many, or incomplete chromosomes because of errors in the formation of sperm or ova.
chromosome abnormalities
A chromosomal abnormality in which the child has inherited an extra 21st chromosome and is, as a result, mentally retarded; also called trisomy 21.
Down syndrome
A sex chromosome abnormality in which females inherit only one X chromosome (XO); they remain small in stature, fail to develop secondary sex characteristics, and may show some mental deficiencies.
Turner syndrome
A sex chromosome abnormality in which males inherit two or more X chromosomes; these males fail to develop secondary sex characteristics and often show deficiencies on tests of verbal abilities.
Klinefelter syndrome
A chromosome abnormality in which one arm of the X chromosome is only barely connected to the rest of the chromosome; the most common hereditary cause of mental retardation.
fragile X syndrome
A service designed to inform people about genetic conditions they or their unborn children are at risk of inheriting.
genetic counseling
In genetics, individuals who possesses a recessive gene associated with a disease and who, although they do not have the disease, can transmit the gene for it to offspring.
carrier
A genetic disease caused by a single, dominant gene that strikes in middle age to produce a deterioration of physical and mental abilities and premature death.
Huntington’s disease
Method of examining physical organs by scanning them with sound waves—for example, scanning the womb and thereby producing a visual outline of the fetus to detect gross abnormalities.
ultrasound
A method of extracting amniotic fluid from a pregnant woman so that fetal body cells within the fluid can be tested for chromosomal abnormalities and other genetic defects.
amniocentesis
An alternative to amniocentesis in which a catheter is inserted through the cervix to withdraw fetal cells from the chorion for prenatal testing to detect genetic defects.
chorionic villus sampling (CVS)
A noninvasive method of prenatal diagnosis involving testing for substances in maternal blood; more recently, analysis of fetal cells that have slipped through the placenta into the mother’s blood.
maternal blood sampling
Prenatal diagnostic procedure in which a mother’s eggs are fertilized in the laboratory using in vitro fertilization techniques, DNA tests are conducted on the first cells that result from mitosis of each
fertilized egg, and only eggs that do not have
chromosome abnormalities or genes associated
with disorders are implanted in the uterus.
preimplantation genetic diagnosis
The scientific study of the extent to which genetic and environmental differences among individuals are responsible for differences among them in traits such as intelligence and personality.
behavioral genetics
The amount of variability in a population on some trait dimension that is attributable to genetic differences among those individuals.
heritability
A method of studying genetic influence that involves deliberately determining whether a trait can be bred in animals through selective mating.
selective breeding
Method of studying genetic and environmental
influence in which the similarity of identical twins is compared to that of fraternal twins, often in studies involving both twins reared together and twins reared apart.
twin study
Method of studying genetic and environmental influence that involves determining whether adopted children are more similar to their biological parents or adoptive parents.
adoption study
The percentage of cases in which a particular attribute is present for both members of a pair of people (e.g. twins) if it is present for one member.
concordance rate
Experiences that individuals living in the same home environment share and that work to make them similar.
shared environmental influences
Experiences unique to the individual that are not
shared by other members of the family and that
tend to make members of the same family different.
nonshared environmental influences
The analysis of particular genes and their effects, including the identification of specific genes that influence particular traits and the comparison of animals or humans who have these specific genes and those who do not.
molecular genetics
A genetically based pattern of tendencies to respond in predictable ways; building blocks of personality such as activity level, sociability, and emotionality.
temperament
The phenomenon in which the effects of people’s genes depend on the kind of environment they experience and in which the effects of the environment depend on their genetic endowment.
gene–environment interaction
A systematic interrelationship between an individual’s genes and that individual’s environment; ways in which genes influence the kind of home environment provided by parents (passive gene–
environment correlation), the social reactions
to the individual (evocative gene–environment
correlation), and the types of experiences the
individual seeks (active gene–environment
correlation).
gene–environment correlation
A genetic disease in which the child is unable to metabolize phenylalanine; if left untreated, it soon causes hyperactivity and mental retardation.
phenylketonuria (PKU)
Interventions that involve substituting normal genes for the genes associated with a disease or disorder; otherwise altering a person’s genetic makeup.
gene therapy
Undifferentiated, primitive cells that
have the ability both to multiply and to differentiate
into a variety of specific cells.
stem cell
