Gamete Formation
Mendel’s ‘factors’ are now called genes
Genotype refers to the specific allelic composition of an individual
Independent assortment: During gamete formation, the segregation of any pair of hereditary determinants is independent of the segregation of other pairs
Random sampling error
N+N sperm
N egg
3n endosperm
Degrees of freedom
Tetrad (bivalent)
Mitosis produces daughter cells that are genetically identical
Meiosis produces daughter cells that are not genetically identical
The daughter cells contain only one homologous chromosome from each pair
The daughter cells contain many different combinations of the single homologues
Spermatocyte--spermatids
In incomplete dominance the heterozygote exhibits a phenotype that is intermediate between the corresponding homozygotes.
overdominance is the phenomenon in which a heterozygote is more vigorous than either of the corresponding homozygotes
Coat color in rabbits is an example of multiple alleles that form a dominance heiarchy.
Codominant: They are both expressed in a heterozygous individual
X-linked gene: Many species have males and females that differ in their sex chromosome composition
X-influenced gene: , sex influence is a phenomenon of heterozygotes: results from sex hormone
Pattern baldness results from over-expression of a gene that converts testosterone to 5-dihydrotestosterone (DHT) which binds receptors and alters expression of many genes
Dosage compensation: to offset differences in the number of gene on the sex chromosomes: Barr body, random X inactivation
Epigenetic inheritance: refers to a pattern in which a modification occurs to a nuclear gene or chromosome that alters gene expression
Genomic imprinting: expression of a gene depends on whether it is inherited from the male or the female parent
DMR: differentially methylated region: methylated—silence H19, unmethylated silence lgf2
PWS. AS
Conditional lethal allele: may kill an organism only
Genotype refers to the specific allelic composition of an individual
Independent assortment: During gamete formation, the segregation of any pair of hereditary determinants is independent of the segregation of other pairs
Random sampling error
N+N sperm
N egg
3n endosperm
Degrees of freedom
Tetrad (bivalent)
Mitosis produces daughter cells that are genetically identical
Meiosis produces daughter cells that are not genetically identical
The daughter cells contain only one homologous chromosome from each pair
The daughter cells contain many different combinations of the single homologues
Spermatocyte--spermatids
In incomplete dominance the heterozygote exhibits a phenotype that is intermediate between the corresponding homozygotes.
overdominance is the phenomenon in which a heterozygote is more vigorous than either of the corresponding homozygotes
Coat color in rabbits is an example of multiple alleles that form a dominance heiarchy.
Codominant: They are both expressed in a heterozygous individual
X-linked gene: Many species have males and females that differ in their sex chromosome composition
X-influenced gene: , sex influence is a phenomenon of heterozygotes: results from sex hormone
Pattern baldness results from over-expression of a gene that converts testosterone to 5-dihydrotestosterone (DHT) which binds receptors and alters expression of many genes
Dosage compensation: to offset differences in the number of gene on the sex chromosomes: Barr body, random X inactivation
Epigenetic inheritance: refers to a pattern in which a modification occurs to a nuclear gene or chromosome that alters gene expression
Genomic imprinting: expression of a gene depends on whether it is inherited from the male or the female parent
DMR: differentially methylated region: methylated—silence H19, unmethylated silence lgf2
PWS. AS
Conditional lethal allele: may kill an organism only