chpt 9 terms

ABO blood groups

genetically determine classes of human blood that are based on the presence or absence of carbs or A and B or the surface of red blood cells

alleles

one of two or more alternative forms of a gene that occupy the same locus on a chromosome

carrier

individuals who are heterozygous for a recessively inherited disorder and who therefor does not show symptoms of that disorder

character

a heritable feature that varies among individuals

chromosome theory of inheritance

states that genes are located on chromosomes, and the behavior of chromosomes during meiosis explains the patterns of inheritance observed by Mendel

codominance

a genetic phenomenon where two versions of a gene, called alleles, are expressed equally in an organism, resulting in the appearance of both traits

cross

the intentional breeding of two different organisms to combine their genetic material in their offspring

dihybrid cross

a mating experiment between two organisms that are identically hybrid for two traits

dominant alleles

a version of a gene that is expressed over a recessive allele, even when only one copy of the dominant allele is present

epigenetic inheritance

the process by which epigenetic marks and modifications are passed down from one generation to the next, without changing the DNA structure

F1 generation

the first generation of offspring that results from crossing two different parents

F2 generation

the second filial generation, or the offspring of the first filial generation (F1)

genetics

the study of genes, heredity, and genetic variation in organisms

genotype

an organism's complete set of genetic material, or its genetic makeup

heredity

the process by which traits or characteristics are passed from parents to their offspring through genetic material

heterozygous

an organism has two different versions (alleles) of a specific gene

homozygous

an organism has two identical copies of the same gene, one inherited from each parent, for a specific trait,

hybrid

an organism that is the offspring of two parents belonging to different species, subspecies, or varieties

incomplete dominance

a genetic pattern where two alleles blend to create a new phenotype, or a mix of the two, instead of one allele being completely dominant over the other

law of independent assortment

when reproductive cells form, different genes separate independently of each other.

linked gene

genes that are located close together on the same chromosome and are likely to be inherited together

locus

mendel’s law of segregation

during the formation of gametes (sperm or egg cells), the two alleles of a gene pair separate from each other

monohybrid cross

a breeding experiment between two organisms that differ in a single genetic trait, or locus

P generation

the parental generation in a genetic cross, or the first generation of organisms in an experiment on inheritance

pedigree

a diagram that visually represents the inheritance of a specific trait or genetic condition within a family across generations

phenotype

a term in genetics that refers to the observable characteristics of an organism, including its physical traits, behavior, and biochemical properties:

pleiotropy

a genetic phenomenon where a single gene or DNA variant affects multiple traits or phenotypes that may seem unrelated:

polygenic inheritance

a pattern of genetic inheritance where multiple genes control a trait or characteristic

Punnett square

a square diagram that is used to predict the genotypes of a particular cross or breeding experiment

recessive allele

a type of allele that only expresses a trait when two copies are present in an individual:

rule of multiplication

to calculate the probability of two or more independent events occurring together, you multiply the individual probabilities of each event happening separately

sex linked gene

a gene that is located on a sex chromosome, such as the X or Y chromosome, and has a specific pattern of inheritance and expression that varies between males and females.

testcross

a genetic experiment that determines an organism's genotype by crossing it with an organism that has a known genotype:

trait

a specific characteristic of an organism, often determined by genes, which can be observed physically or behaviorally,

wild type

the phenotype (observable characteristic) that is most commonly found in a natural population of organisms,