Ch 12 Inheritance, Genes, and Chromosomes

• created theory of inheritance
• used pea plants, controlled pollination

A trait passed from parent to offspring

observed trait that is the only one present throughout many generations

trait that dissapears for a generation then reappears

Appears in the next generations

proves that each parent contributes genetic material equally

• Each plant has 2 genes for each character
• heritible units are discrete particles

All genes in an organism

different forms of a gene

individuals with 2 copies of the same allele

individuals with 2 different alleles

• physical apearance of an organism
• EX-spherical seeds, wrinkled seeds

• the genetic make up
• EX-SS, Ss, ss

• two copies of a geene seperate in reproduction
• EX- an Ss parent gives on S to one offspring and the s to the other

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• helps predict allele combinations

• a site on a chromosome where the gene resides
• it encodes a particular character

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• helps detirmine whether an individual is homozygous or heterozygous
• process-crossing an unknown individual with a homozygous recessive

• crossing SsYy and SsYy
• Has 2 genes and are identical

• alleles of different genes assort independently during gamete formation
• *only applies to genes on different chromosomes*

• If the event is certain probability=1
• If the event cannot happen probability=0
• All other events in between have probability between 0 and 1

rare, stable, inherited changes in the genetic material

allele present in most of population

locus with wild-type alleles present < 99% of the time

alleles that are neither dominant or recessive

2 alleles at one locus producing phenotypes that are both present in the heterozygote

a single allele that can have multiple phenotypic effects

phenotypic expression of one gene being influenced by another

mating among close relatives

a cross between 2 different true breeding homozygotes resulting in stronger, larger phenotypes

proportion of individuals with a certain genotype that show the phenotype

degree in which genotype is expressed in an individual

genes taht determine complex characters

formed by all of the loci in a chromosome group

genes at different loci on the same chromosome sometimes seperate

where recombinant offspring appear

• can be made using recombinant frequencies
• shows the arrangement of genes along a chromosome

Map unit (unit=centimorgan, cM)

• "one house"
• both male and female prodused from one

• "two houses"
• male and female produced by seperate individuals

• determines sex of an individual
• EX- XY, XX

both sexes having 2 copies of all other chromosomes

• sister chromosomes fail to seperate in meiosis
• resullts in an abnormal amount of chromosomes

• X-turners syndrome
• XXY-klinefelter syndrome

• Y chromosome encoded protien
• if present=male offspring
• not present=female offspring

• results in outward characteristics of each sex (not detirmined directly by Y chromosome)
• determined by genese on autosomes and X chromosomes controlling hormones

• males only have 1 copy
• -y chromosomes carry few genes
• -x chromosomes carry many genes

a character is governed by loci on the sex chromosomes

a projection that initiates contact between bacteria

cytoplasmic bridge that forms between cells

small circular chromosomes found in bacteria