Biology-H Chapter 13: Patterns in Inherited Traits

What did Mendel discover?

genes

Diploid cells have ____ so they have ____ of the each gene

homologus chromosones; 2 copies

Which allele is more likely to make a protein?

dominant

Which allele is less likely to make a protein?

recessive

dominant

Refers to an allele that masks the effect of a recessive allele paired with it in heterozygous individuals.

genotype

The particular set of alleles that is carried by an individual's chromosomes.

heterozygous

Having two different alleles at the same locus on homologous chromosomes.

homozygous

Having two identical alleles at the same locus on homologous chromosomes.

hybrid

A heterozygous individual.

locus

A particular location on a chromosome.

phenotype

An individual's observable traits.

recessive

Refers to an allele with an effect that is masked by a dominant allele on the homologous chromosome.

Genes can be identical or it can have different variations (___)

alleles

A phenotype is influenced by the organism's…

genotype + environment

If an organism is a hybrid, what is the deciding factor on how a phenotype is displayed?

the interactions between alleles

P

Dominant Allele

p

Recessive Allele

PP

Homozygous dominant

pp

Homozygous recessive

Pp

Heteroxygous

PP, Pp, pp

Genotype

Purple petals

phenotype

Breeding ___ for a trait means that, new ___ aside, all offspring have the ___ of the trait as the parent(s), generation after generation.

true; mutations; same form

What happens when homologous chromosomes separate during meiosis?

the genes separate too

A homozygous dominant chromosome, after meiosis, produces...

dominant alleles

A homozygous recessive chromosome, after meiosis, produces...

recessive alleles

A heterozygous chromosome, after meiosis, produces...

both dominant and recessive alleles

When does monohybrid crosses start?

When two individuals who breed true for a different version of a trait cross

A homozygous dominant and a homozygous recessive cross, what will always be the outcome?

a heterozygous individual

Who must be the parents in a trestcross?

a homozygous recessive parent and a parent with a dominant phenotype

True or false: in a trestcross, we know both the parents' genotype and phenotype

false

Trestcross: If all the offspring have dominant traits, what is the genotype of the unknown parent?

homozygous dominant

Trestcross: If at least one offspring has a recessive trait, what is the genotype of the unknown parent?

heterozygous

Trestcross: The patterns of the ___ among the ___ reveal the genotype of the unknown parent.

traits; offspring

Who must be the parents in a monohybrid cross?

two individuals who are heterozygous for the same/identical trait?

What will be the ratio of phenotype (dominant to recessive) in a monohybrid cross?

3:1

What will be the ratio of genotype (homozygous to heterozygous) in a monohybrid cross?

2:2

According to the law of segregation, what happens to the alleles in any locus?

they are put into separate gametes

The law of ___ states that an organism has two copies (___) of every gene, but during reproduction, these copies ___ so that each ___ or ___ cell gets only ___.

segregation; alleles; separate; egg; sperm; one copy

A monohybrid cross studies the relationship between 2 ___ on ___ gene.

alleles; gene

Mm x Mm

monohybrid cross

PpMm x PpMm

dihybrid cross

dihybrid

an organism heterozygous for two different traits

Mendel's Law of ___ ___ states that different genes (and their alleles) separate ___ from one another during the formation of sperm or egg cells.

independent assortment; independently

What happens after random assortment if two alleles are on different chromosomes?

They are developed in two cells

What happens after random assortment if two alleles are on the same chromosome but far away?

there is high random assortment

What happens after random assortment if two alleles are on the same chromosome and close to each other?

random assortment doesn't happen

Linked genes

genes in chromosome which are not affected by random assortment

Law of segregation

A diploid cell has two copies of every gene that occurs on its homologous chromosomes. Two alleles at any locus are distributed into separate gametes during meiosis.

Monohybrid cross

Cross between two individuals identically heterozygous for one gene; for example Aa × Aa.

Punnett square

Diagram used to predict the genotypic and phenotypic outcome of a cross.

Testcross

Method of determining the genotype of an individual with a dominant phenotype: a cross between the individual and another individual known to be homozygous recessive.

Dihybrid cross

Cross between two individuals identically heterozygous for two genes; for example AaBb × AaBb.

Law of independent assortment

During meiosis, alleles at one gene locus on homologous chromosomes tend to be distributed into gametes independently of alleles at other loci.

Linkage group

All of the genes on a chromosome.

codominance

Effect in which the full and separate phenotypic effects of two alleles are apparent in heterozygous individuals.

epistasis

(epp-ih-STAY-sis) Polygenic inheritance, in which a trait is influenced by multiple genes.

incomplete dominance

Inheritance pattern in which one allele is not fully dominant over another, so the heterozygous phenotype is an intermediate blend between the two homozygous phenotypes.

multiple allele system

Gene for which three or more alleles persist in a population at relatively high frequency.

pleiotropic

(ply-uh-TROH-pick) Refers to a gene that affects multiple traits.