PSY 2410 Chapter 3

are composed of cells that manufacture proteins according to a code of instructions stored in genes

The chemical composition of the molecules that contain the genes, which are the chemical instructions for cells to manufacture various proteins

One of the 46 molecules of DNA (in 23 pairs) that virtually every cell of the human body contains and that, together, contain all the genes

A reproductive cell (in humans, a sperm or ovum)

The single cell formed from the union of two gametes

A small section of a chromosome; the basic unit for the transmission of heredity. Consists of a string of chemicals that provide instructions for the cell to manufacture certain proteins

A variation that makes a gene different in some way from other genes for the same characteristics (polymorphic). Some have SNPs (single-nucleotide polymorphisms), which is a variation in only one part of the code

The full set of genes that are the instructions to make an individual member of a certain species

Genes with various repeats or deletions of base pairs

T-A-G-C (thymine, adenine, guanine, cytosine)

NON-sex chromosomes, aka not the 23rd pair, humans usually have 44

Two genes of one pair that are exactly the same in every letter of their code. Most gene pairs are this

Two genes of one pair that differ in some way. Typically, one allele has only a few base pairs that differ from the other member of the pair

The sex chromosomes, XX for females, XY for males (SRY gene)

The phenomenon where the same allele can affect embryos differently, depending on whether it came from the mother or the father

The study of how the environment alters genetic expression. It begins at conception and continues lifelong, and many of the best human qualities are results of epigenetic changes

All of the microbes (bacteria, viruses, fungi, etc.) with all their genes in a community. Several hundred species of microbes cause epigenetic changes, and few microbes are the same in everyone

The zygote begins duplication and division. First the 23 pairs of chromosomes duplicate, then the two sets move toward opposite sides, then the cell splits.

Newborns have ~26 billion cells, adults have ~37 trillion cells, the same 46 chromosomes, and the same thousands of genes as the original zygote

Cells from which any other specialized types of cell can form, can be edited (CRISPR)

After about the eight-cell stage, cells specialize, taking on different forms and reproducing at various rates depending on location

Fertilization that takes place outside a woman's body. Involes mixing sperm with ova that have been surgically removed from the woman's ovary

Slightly higher incidence of congenital malformations and preterm birth, and many nations have laws about IVF, making it a polical issue

Twins who originate from one zygote that splits apart very early in development, aka identical twins/triplets/quadruplets

Twins who are formed when two separate ova are fertilized by two separate sperm at roughly the same time, aka fraternal twins, have only half of their genes in common

An organism's entire genetic inheritance, or genetic potential

The observable characteristics of a person, including appearance personality, intelligence, and all other traits

Trait influenced by many genes

Trait affected by many factors, both genetic and environmental

Because of an allele or environmental influence, a person may or may not be affected by specific genes and experiences

The international effort to map the complete human genetic code, it was essentially completed in 2001, though analysis is ongoing

Humans have fewer genes than previously believed. While humans all have virtually the same genes, they differ in small ways in the details of the base pairs, alleles, or SNPs, which are not identical from one person to another

Interactions among genes and alleles whose effects add something to some aspect of the phenotype, for example, height is influenced by over 1000 alleles

Dominant genes are far more influential than recessive genes, carried in the genotype, and are reflected in the phenotype

Person whose genotype includes a gene that is not expressed in the phenotype, unexpressed gene is passed on to offspring

A gene carried on the X chromosome. If a male inherits an X-linked recessive trait from his mother, he expresses the trait because the Y has no counteracting gene. Females are more likely to be carriers of X-linked traits but are less likely to express them.

Involves alleles that create addictive pull, is genetic but much more, phenotype is affected by both genotype and environment

Genes, personality traits, age, social contexts, sex, gender

Age - limited focus at birth; change in eyeball shape at puberty; decreasing myopia at middle age
Genes - heritability of about 75%
Social Context - environment (time indoors, reading), homework, lack of play

A statistic that indicates what percentage of the variation in a particular trait within a particular population, in a particular context and era, can be traced to genes

distinct, with particular vulnerabilities, characteristics, and strengths

more or fewer than 46 chromosomes. Almost all uneven zygotes fail to duplicate, divide, differentiate, implant, and grow and are miscarried very early in pregnancy

Miscounts at the 23rd pair are more common and less harmful than miscounts in the autosomes. A human must have at least 44 autosomes and one X chromosome to survive

Down syndrome (trisomy-21), cognition and language develop slowly, common trait of friendlyness

XXY (Klinefelter syndrome)
XYY (Jacob's syndrome)
XXX (triple X syndrome)
XO (only one sex chromosome, Turner Syndrome)

Klinefelter syndrome, typical male characteristics at puberty do not develop and breasts may develop, can have some intellectual difficulties especially in language (1 in 700 males)

Jacob's syndrome, typically tall, risk of intellectual difficulties especially in language (1 in 1,000 males)

Triple X syndrome, typical appearance, difficulties in most intellectual skills (1 in 1,000 females)

Turner Syndrome; short, often webbed neck, sexondary sex characteristics (breasts, menstruation) don't develop; some learning difficulties especially math and spatial understanding, difficulty recognizing facial emotion expressions (1 in 6,000 females)

Many of the 7,000 known single-gene disorders are this; most are mild but severe conditions are rare because people with them typically die before reproducing, and dominant conditions that appear in adulthood can be passed down

More numerous because they are passed down by carriers who are unaware of their genotype

Common ones include cystic fibrosis, thalassemia, and sickle cell disease. Some are X-linked: hemophilia, Duchenne muscular dystrophy, fragile X syndrome

skin color, height, weight, anxiety (benefical and harmful)

Data can reveal risks but not reality, most reported research is on Western Europeans, genetic research is proceeding faster than practical care, and most genetic differences are "variants of unknown significance."

Far greater demand for genetic counselors than there are people. Requirements include understanding and communicating complex biological and statistical material, knowing recent discoveries, explaining odds and consequences, asking in advance about circumstances