Part 2 - Meiosis & Genetics Bio Final

ABO blood groups

The human blood types A, B, AB, and O determined by multiple alleles and codominance.

allele

An alternative form of a gene.

amniocentesis

A prenatal test that examines fetal cells from amniotic fluid.

carrier

A person who has one recessive allele for a trait but does not show the trait.

character

A heritable feature that varies among individuals.

chromosome theory of inheritance

The theory that genes are located on chromosomes.

codominant

A pattern of inheritance in which both alleles are fully expressed.

complete dominance

A pattern of inheritance in which one allele completely masks another.

cross

The mating of two organisms to study inheritance.

dihybrid cross

A genetic cross involving two different traits.

dominant allele

An allele that is expressed whenever it is present.

F1 generation

The first generation of offspring from a parental cross.

F2 generation

The offspring produced by crossing members of the F1 generation.

genetics

The study of heredity and inheritance.

genotype

The genetic makeup of an organism.

heredity

The passing of traits from parents to offspring.

heterozygous

Having two different alleles for a gene.

homozygous

Having two identical alleles for a gene.

Huntington's disease

A dominant genetic disorder that causes nervous system degeneration.

hybrid

The offspring of parents with different traits.

incomplete dominance

A pattern of inheritance in which the heterozygous phenotype is intermediate between the two homozygotes.

law of independent assortment

Genes for different traits are inherited independently of one another.

law of segregation

The two alleles for a gene separate during gamete formation.

linkage map

A map showing the relative locations of genes on a chromosome.

linked genes

Genes located close together on the same chromosome that tend to be inherited together.

locus (plural, loci)

The specific location of a gene on a chromosome.

monohybrid cross

A genetic cross involving one trait.

pedigree

A family tree used to trace inheritance of traits.

P generation

The parental generation in a genetic cross.

phenotype

The observable traits of an organism.

pleiotropy

The ability of one gene to affect multiple traits.

polygenic inheritance

Inheritance in which multiple genes contribute to one trait.

Punnett square

A diagram used to predict possible genetic outcomes.

recessive allele

An allele that is expressed only when two copies are present.

recombination frequency

The percentage of offspring showing new combinations of traits due to crossing over.

rule of addition

A probability rule used when either one event or another can occur.

rule of multiplication

A probability rule used when two independent events occur together.

sex chromosomes

Chromosomes that determine biological sex.

sex

linked gene

sickle

cell disease

testcross

A cross used to determine an unknown genotype.

trait

A specific characteristic that can be inherited.

true

breeding

meiosis

A type of cell division that produces four genetically different haploid cells.

gamete

A reproductive cell such as a sperm or egg.

crossing over

The exchange of DNA between homologous chromosomes during meiosis.

autosome

A chromosome that is not a sex chromosome.

sex chromosome

A chromosome involved in determining sex.

independent assortment

The random distribution of chromosome pairs during meiosis.

fertilization

The fusion of sperm and egg cells to form a zygote.

zygote

A fertilized egg cell.

variation

Differences among individuals in a population.

diploid

Having two sets of chromosomes (2n).

haploid

Having one set of chromosomes (n).

homologous chromosomes

Chromosome pairs that carry the same genes but may have different alleles.

nondisjunction

The failure of chromosomes to separate properly during meiosis.

deletion

A chromosomal mutation in which part of a chromosome is lost.

duplication

A chromosomal mutation in which part of a chromosome is repeated.

inversion

A chromosomal mutation in which a chromosome segment reverses direction.

translocation

A chromosomal mutation in which a chromosome segment attaches to a different chromosome.