Studied by 1 personhomologous chromosome
a chromosome pair that contain similar alleles as well are similar in shape and size
diploid cell
a cell that contains 46 chromosomes or 23 pairs(results from the 1st stage of meiosis)
haploid cell
A cell that has 23 chromosomes(examples are eggs and sperm/gametes)
crossing over
the exchange of DNA during meiosis between homologous chromosomes
Genetic recombination-crossing over, independent assortment, segregation of chromosomes, random fertilization
How does genetic variation occur?
nondisjunction
homologous chromosomes fail to separate during meiosis 1, or sister chromatids fail to separate during meiosis 2
4 haploid cells
What results from meiosis?
23 pairs
how many pairs of chromosomes do humans have?
karyotype
an organized profile or picture of a person's chromosomes. used to quickly identity genetic disorders
size, shape, and gene banding patterns
How are homologous chromosomes identified?
2 X chromosomes
female
1 x and 1 y chromosome
male
Gregor Mendel
through his work on pea plants, discovered the fundamental laws of inheritance. He deduced that genes come in pairs and are inherited as distinct units, one from each parent. Mendel tracked the segregation of parental genes and their appearance in the offspring as dominant or recessive traits.
independent assortment
chromosomes are inherited independently of each other
Law of segregation
an individual inherits 2 copies of each gene but only one copy of each gene is donated to each gamete
genotype
the genetic combination that results in a certain allele
phenotype
physical characteristic resulting from an allele
incomplete dominance
genotype that has 2 traits that appear in the phenotype as a combination of both
codominance
genotype that has 2 dominant alleles which both coexist in the phenotype
Note
Flashcard