Unit 6 Heredity Flashcards
Genetics
The Study of heredity and heredity variation
Heredity
The transmission of traits from one generation to the next
Asexual
a mode of reproduction in which a new offspring is produced by a single parent
Sexual
Two parents(male/female)
Offspring are unique combinations of genes from parents
Genetically varied from parents and sibling
Homologous Chromosomes
A pair of chromosomes that carry the same genetic information
Karyotypes
Display of chromosomes pairs arranged by size and length
Somatic(body) Cells
Diploids(2n): Two complete sets of each chromosomes
Gametic(sex) Cells
Haploid(n): One set of each chromosomes
Autosomes
Type of DNA that is packaged in chromosomes that do not determine sex
Sex Chromosomes
Type of DNA that is packaged in chromosomes with X and Y
Egg: X Sperm: X or Y
Life Cycle
Sequence of stages in the reproductive history of an organism from conception to its own reproduction
Meiosis
A process that create haploid (gamete cells) in sexually reproducing diploid(somatic) organisms
Result with half the number of chromosomes as the parent cell
Key Events in Meiosis
Prophase I
Metaphase I
Anaphase I
Crossing Over
produces recombinant chromosomes(Exchange genetic materials)
Independent assortment Law
two different genes gets sorted into independent.
Random Fertilization
Any sperm can fertilize any egg
How does Meiosis Lead to Genetic Variation?
1) Crossing Over
2) Independent assortment of chromosomes
3) Random Fertilization
True Breeding
an organism that always passes down certain phenotypce traits (i.e. physically expressed traits) to its offspring of many generations.
P generation
True- breading parental generation
F1 Generation
Hybrid(mix) offspring of P generation
F2 Generation
Offspring of the F1 generation
Punnett Square
Diagram used to predict the allele combinations of offspring from a cross with known genetic compositions
Homozygous
An organism that has a pair of identical alleles for characters(AA,aa)
Heterozygous
An organism has two different alleles for a gene(Aa)
Genotype
The genetic makeup(alleles/letters) of an organism
Phenotype
An organism appearance, which is determined by the genotype
Purpose of testcross
Helps determine if the dominant trait is homozygous dominant or heterozygous.
Segregation Law
When organism makes gametic cells( A or a)
Pp x Pp produces 3:1 ratio
Monohybrid crosses
A cross between the F1 hybrids(BbxBb)
Independent Assortment Law
alleles of two (or more) different genes get sorted into gametes independently of one another.
Rules for Independent Assortment Law
1) Genes that are located on different chromosomes(not homologous)
2) Genes that are vary far apart on the same chromosomes
Dihybrid Crosses
The law of indapendent assortment was determent by doing crosses between plants that were true breeding for two traits, which produced F1 hybrid known as dihybrid (YYRR x yyrr)
produces a 9:3:3:1 phenotypic ratio
Pedigrees
Family trees that gives a visual of inheritance patterns of particular traits
how to read pedigrees
If a trait is dominant, one parent must have the trait. If a trait is X-linked, then males are more commonly affected than females.
