Genetics Chapter 5 - Grade 11

Trait

A specific characteristic or feature of an organism

Ex, flower color in a plant

True breeding

organisms that exhibit the same traits, generation after generation

Cross

the fertilization of a female gamete of specific genetic origin with a male gamete of specific genetic origin

P generation

Parental Generation

In breeding, the organisms initially crossed and are typically true breeding

F1 generation

the offspring of a cross of the P generation

(f = filial)

Monohybrid cross

Cross of 2 individuals that differ by one trait

F2 generation

the offspring of a cross between the F1 generation

monohybrid cross of heterozygous predicted phenotype (in f2? I think, disregard what's in brackets if I'm wrong)

3:1 ratio

Law of segregation

traits are determined by pairs of alleles that segregate during meiosis so that each gamete receives one allele

Dominant

The form of a trait that always appears when an individual has an allele for it

Recessive

the form of a trait that only appears when an individual has 2 alleles for it

Genotype

The combination of alleles for any given trait, or the organism's entire genetic make up

YY, Yy, yy

Phenotype

The physical and physiological traits of an organism

(visible traits?) --> YY = yellow seeds

Homozygous

An organism that has two identical alleles of a gene

Heterozygous

An organism that has two different alleles of a gene

Punnet Square (What is it?)

A grid used to illustrate all possible genomes and phenotypes of offspring from genetic crosses

Punnet Square (What can it be used to predict?)

phenotypes and genotypes of offspring from a monohybrid cross

Punnet Square (step a)

when working with 1 gene make a box and divide it into 4 squares

Punnet Square (step b)

above squares, write the genotypes of the gametes from one parent. Often, the female parent's gametes are placed here

Punnet Square (step c)

Beside the squares, on the left, write the genotypes of the gametes from the other parent

Punnet Square (part d)

inside each square, write the symbols for the allele above it and the allele beside it . The upper-case letter is always placed first. The genotypes inside the squares are the genotypes of the offspring in the ratio that would be expected for the cross.

Test Cross

a cross between a parent of unknown genotype and a homozygous recessive parent

(if any offspring show the recessive phenotype, the unknown genotype of the parent must be heterozygous)

dihybrid cross`

The inheritance of 2 traits

A cross of 2 individuals that differ in 2 traits due to 2 different genes

P : YYRR x yyrr (true-bred)
F1: YyRr
F2: 9 : 3 : 3 : 1

A dihybrid cross of individuals for both traits yields offspring with a predicted phenotype ratio of (f2? i think, disregard whats in brackets if I'm wrong)

9:3:3:1

9 - displays the dom forms of both traits
3 - displays one dom and 1 recessive form of each trait
3 - displays the other dom / recessive pair of traits
1 - displaying both recessive forms of each trait

law of independent assortment

during gamete formation, the 2 alleles for 1 gene segregate or assort independently of the alleles for other genes

chromosome theory of inheritance

traits determined by genes are inherited through the movement of chromosomes during meiosis

Pedigree

flow chart that uses symbols to show the inheritance patterns of traits in a family over many generations

Pedigree: square

male

Pedigree: circle

female

Pedigree: circle-square

mating

pedigree: line on top, a triangle in the middle, and 2 circles left and right (everything connected by triangle)

Identical Twins

Pedigree: line on top, triangle without a bottom (not connecting the 2 circles) and 2 circles left and right

non identical twins

Pedigree: Bolded circle or square

Affected individuals

Pedigree: crossed out circle or square

dead individual

Pedigree: diamond / square tilted / rombus

sex unknown

Autosomal inheritance

inheritance of traits determined by genes on the autosomal chromosomes

Autosomal dominant

the inheritance of a dominant phenotype whose gene is on an autosomal chromosome

Autosomal recessive

the inheritance of a recessive phenotype whose gene is on an autosomal chromosome

Autosomal Dominant or Recessive: Neurofibromatosis

Autosomal Dominant

Autosomal Dominant or Recessive: Huntington’s

Autosomal Dominant

Autosomal Dominant or Recessive: Retinoblastoma

Autosomal Dominant

Autosomal Dominant or Recessive:

Autosomal Recessive

Autosomal Dominant or Recessive: Marfan syndrome

Autosomal Dominant

Autosomal Dominant or Recessive:

Autosomal Dominant or Recessive:

Autosomal Dominant or Recessive:

Autosomal Dominant or Recessive:

Autosomal Dominant or Recessive:

Autosomal Dominant or Recessive:

Autosomal Dominant or Recessive: