Bio genetics vocab

trait

a specific characteristic or feature of an organism that can be inherited genetically.

true-breeding

They only have one trait type - Homozygous

produces identical offspring

hybrid

the offspring produced by crossbreeding two different species, varieties, subspecies, or genera

P generation

parental- where you start the experiment

F1 generation

filial - child/offspring

F2 generation

the cross between two children from F1

alleles

• variation of a gene

• different alleles vary in the sequence of nucleotides at the specific locus of a gene

dominant allele

generally the functioning protein

recessive allele

generally the malfunctioning gene

law of segregation

allele pairs separate during gamete formation, so each gamete receives only one allele for each gene.

during meiosis, alleles segregate

• anaphase, anaphase I, anaphase II

• homologous chromosomes separate

homozygous

same alleles

heterozygous

different alleles

phenotype

looks

ex) red stem, short leaves, round seed

genotype

genes (Rr, NN, mm)

test cross

taking an unknown dominant and crossing it with a recessive

• based on offspring, you can determine the type of dominance in parent

dihybrid cross

a genetic mating experiment that tracks the inheritance of two different traits simultaneously between two organisms that are both heterozygous for both traits

• ex) seed color, seed shape

• AaBb x AaBb

law of independent assortment

Random alignment of chromosomes

homologous pairs do not influence eachother when they line up in metaphase I

• INCREASES diversity

incomplete dominance

heterozygote shows an intermediate, blended phenotype

• Ex)

• RR= red

• rr= white

• Rr= pink

complete dominance

a form of Mendelian inheritance where one dominant allele completely masks the presence of a recessive allele in a heterozygous organism's genotype

codominance

2 alleles affect the phenotype equally and separately (not a blend)

ex) blue with yellow spots

multiple alleles

there are more than two versions (alleles) for a single gene within a population, even though an individual organism only inherits two (one from each parent) for that specific gene, like the A, B, and O alleles for human blood type

pleiotopy

one gene affects more than one phenotypic character

-Most genes are pleiotropic

epistasis

one gene completely masks another gene

polygenic inheritance

some phenotypes are determined by additive effects of 2 or more genes on a single character

• normal distribution for a phenotype= polygenic (bell curve)

carrier

an organism or a molecule that carries a specific gene, often without showing symptoms themselves, but capable of passing it to offspring or others

chromosome theory of inheritance

states that genes are located on chromosomes, and the behavior of chromosomes during meiosis physically explains Gregor Mendel's laws of inheritance

wild type

most common

mutant phenotype

least common

sex-linked genes

genes are on the sex chromosomes #23

the gametes

linked genes

genes on the same chromosome

• the farther they are from each other, the higher the crossover rate

genetic-recombination

the process where DNA is mixed and rearranged, creating new combinations of genes that are different from either parent.

parental type

the process where DNA is mixed and rearranged, creating new combinations of genes that are different from either parent.

recombinants

Recombinants (recombinant types) are offspring that have a new combination of traits that does NOT match either parent.

barr body

A Barr body is a condensed, inactive X chromosome found in the cells of individuals with more than one X chromosome.

nondisjunction

chromosomes don't separate properly during meiosis

• wrong # of chromosomes

aneuploidy

wrong # of chromosomes

trisomy

cells have 3 copies of a chromosome

monosomy

cells have only 1 copy of a chromosome

polyploidy

when a cell or organism has more than two complete sets of chromosomes.

(full sets)

deletion

ABCDE →ABDE

duplication

ABCDE →ABBCDE

inversion

ABCDE → ACBDE

translocation

ABCDE GHI → GHCDE ABI

Null hypothesis

The null hypothesis is the default assumption in an experiment that there is no effect, no difference, or no relationship between variables.