E. Mavis Hetherington,
University of Virginia
Ross D. Parke,
University of California
Mark Schmuckler,
University of Toronto at Scarborough
Below are this chapter's featured key terms. The textbook's full glossary is also available for online searching.
| allele | An alternative form of a gene; typically, a gene has two alleles, one inherited from the individual's mother and one from the father.
|
 |
|
|
| alphafetoprotein assay (AFP) | A blood test performed prenatally to detect such problems as Down syndrome, the presence of multiple embryos, and defects of the central nervous system.
|
|
|
|
| amniocentesis | A technique for sampling and assessing fetal cells for indications of abnormalities in the developing fetus; performed by inserting a needle through the abdominal wall and into the amniotic sac and withdrawing a small amount of the amniotic fluid.
|
|
|
|
| autosomes | The 22 paired non-sex chromosomes in males and females that determine the development of most body structures and attributes.
|
|
|
|
| canalization | The genetic restriction of a phenotype to a small number of developmental outcomes, permitting environmental influences to play only a small role in these outcomes.
|
|
|
|
| chorionic villi sampling | A technique for sampling and assessing cells withdrawn from the chorionic villi, projections from the chorion that surrounds the amniotic sac; cells are withdrawn either through a tube inserted into the uterus through the vagina or through a needle inserted through the abdominal wall.
|
|
|
|
| chromosomes | Threadlike structures, located in the central portion, or nucleus, of a cell, that carry genetic information to help direct development.
|
|
|
|
| co-dominance | A genetic pattern in which heterozygous alleles express the variants of the trait for which they code simultaneously and with equal force.
|
|
|
|
| concordance rate | The percentage of cases in which a characteristic or trait exhibited by one member of a twin pair is also exhibited by the other twin.
|
|
|
|
| crossing over | The process by which equivalent sections of homologous chromosomes switch places randomly, shuffling the genetic information each carries.
|
|
|
|
| deoxyribonucleic acid (DNA) | A ladderlike molecule that stores genetic information in cells and transmits it during reproduction.
|
|
|
|
| dizygotic | Characterizing fraternal twins, who have developed from two separate fertilized eggs.
|
|
|
|
| dominant | Describing the more powerful of two alleles in a heterozygous combination.
|
|
|
|
| Down syndrome | A form of chromosome abnormality in which the person suffers disabling physical and mental development and is highly susceptible to such illnesses as leukemia, heart disorders, and respiratory infections.
|
|
|
|
| evocative influences | When inherited tendencies evoke certain responses from others, thus shaping their social environment.
|
|
|
|
| fragile X syndrome | A form of chromosome abnormality, more common in males than in females, in which an X chromosome is narrowed in some areas, causing it to be fragile and leading to a variety of physical, psychological, and social problems.
|
|
|
|
| gene | A portion of DNA that is located at a particular site on a chromosome and that codes for the production of certain kinds of proteins.
|
|
|
|
| genotype | The particular set of genes that a person inherits from his or her parents.
|
|
|
|
| hemophilia | A disorder caused by an X-linked recessive gene in which the blood fails to clot; found more often in males than in females.
|
|
|
|
| heritability factor | A statistical estimate of the contribution made by heredity to a particular trait or ability.
|
|
|
|
| heterozygous | Describing the state of an individual whose alleles for a particular trait from each parent are different.
|
|
|
|
| homozygous | Describing the state of an individual whose alleles for a particular trait from each parent are the same.
|
|
|
|
| human behaviour genetics | The study of the relative influences of heredity and environmental forces on the evolution of individual differences in traits and abilities.
|
|
|
|
| Huntington disease | A genetically caused, fatal disorder of the nervous system that begins in midadulthood and is manifested chiefly in uncontrollable, spasmodic movements of the body and limbs and eventual mental deterioration.
|
|
|
|
| Klinefelter's syndrome | A form of chromosome abnormality in which a male inherits an extra X sex chromosome, resulting in the XXY pattern, and has many feminine physical characteristics as well as language deficits and, sometimes, mental retardation.
|
|
|
|
| meiosis | The process by which a germ cell divides to produce new germ cells with only half the normal complement of chromosomes; male and female germ cells (sperm and ovum) each contain only 23 chromosomes so that when they unite the new organism they form will have 46 chromosomes, half from each parent.
|
|
|
|
| mitosis | The process in which a body cell divides in two, first duplicating its chromosomes so that the new, daughter cells each contain the usual 46 chromosomes.
|
|
|
|
| modifier genes | Genes that exert their influence indirectly, by affecting the expression of still other genes.
|
|
|
|
| monozygotic | Characterizing identical twins, who have developed from a single fertilized egg.
|
|
|
|
| niche picking | Seeking out or creating environments that are compatible with one's own (genetically based) predispositions.
|
|
|
|
| nonshared environment | A set of conditions or activities that is experienced by one child in a family and not shared with another child in the same family.
|
|
|
|
| nucleotide | A compound containing a nitrogen base, a simple sugar, and a phosphate group.
|
|
|
|
| ovum | The female germ cell, or egg.
|
|
|
|
| phenotype | Created by the interaction of a person's genetic makeup with the environment; the visible expression of the person's particular physical and behavioural characteristics.
|
|
|
|
| phenylketonuria (PKU) | A disease caused by a recessive allele that fails to produce an enzyme necessary to metabolize the protein phenylalanine; if untreated immediately at birth, damages the nervous system and causes mental retardation.
|
|
|
|
| psychopathology | Psychological and behavioural dysfunction as it occurs in various types of mental disorder.
|
|
|
|
| range of reaction | The notion that the human being's genetic makeup establishes a range of possible developmental outcomes, within which environmental forces largely determine how the person actually develops.
|
|
|
|
| recessive | Describing the weaker of two alleles in a heterozygous combination.
|
|
|
|
| sex chromosomes | In both males and females, the 23rd pair of chromosomes, which determine the individual's sex and are responsible for sex-related characteristics; in females, this pair normally comprises two X chromosomes, in males an X and a Y chromosome.
|
|
|
|
| shared environment | A set of conditions or experiences that is shared by children raised in the same family with each other; a parameter commonly examined in studies of individual differences.
|
|
|
|
| sickle cell anemia | A disorder, caused by a recessive gene, in which the red blood cells become distorted when low in oxygen, causing fatigue, shortness of breath, and severe pain and posing a threat to life from blockage of crucial blood vessels.
|
|
|
|
| sperm | The male germ cell.
|
|
|
|
| temperament | The individual's typical mode of response to the environment, including such things as activity level, emotional intensity, and attention span; used particularly to describe infants' and children's behaviour.
|
|
|
|
| Turner syndrome | A form of chromosome abnormality found in females, in which secondary sex characteristics develop only if female hormones are administered and in which abnormal formation of internal reproductive organs leads to permanent sterility.
|
|
|
|
| ultrasonography | A technique that uses sound waves to visualize deep body structures; commonly used to reveal the size and structure of a developing fetus. Also called ultrasound.
|
|
|
|
| X-linked genes | Genes that are carried on the X chromosome and that, in males, may have no analogous genes on the Y chromosome.
|
2002 McGraw-Hill Higher Education