chp 10: patterns of inheritance

developed the basic principles of inheritance after working with garden peas in an effort to discover how variation arose in offspring

because of the pea plant is easy to cultivate, has short generation time, normally self-polinates but can be cross-pollinated by hand

offspring that have the same traits as the parent plants

pollen arrives at the stigma of the same plant

pollen from one plant moves to a different plant

law of segregation and law of independent assortment

a tool which charts the possible combinations of alleles in offspring from two parents

the location of genes on the chromosome

the actual alleles for a gene (molecular)

the physical expression of the genotype (visual)

2 identical alleles

2 different alleles

used to determine whether or not an individual with the dominant trait has two dominate factors or one dominate, one recessive (reveals the unknown genotype of dominant individuals, they could be heterozygous or homozygous dominant)

a parent gives just one allele of their gene to each gamete (their offspring) they produce. ex: Aa, one gamete will receive A and the other will receive a. the gamete is then fertilized to double the allele so each organism has 2 copies of the gene

each pair of factors separate independently of each other (different genes and alleles are inherited independtly and have no link with each other. ex: can inherit tall and green trait), all possible combinations of factors can occur in the gametes

9:3:3:1

they would only express the dominant trait, however they would all be heterozygous and be carriers of the recessive trait

a recessive allele may be expressed by crossing various gametes

why you share similar characteristics with your relatives

neither allele is dominant over each other; causes a heterozygote to express an intermediate phenotype (it will express a blend of the phenotypes)

three or more distinct alleles for a particular gene. for example: the ABO blood group in humans is inherited by three alleles

both traits will be expressed equally in the heterozygote

a trait is determined by multiple genes

traits that are INFLUENCED by multiple genes and environmental factors (ex: skin color, height, or diabetes, cancer)

diabetes, schizophrenia, allergies, cancer

the homologous chromosomes segregate, each gamete receiving one set, and that the segregation of one pair is independent of others; meiosis is the fundamental process underlying mendel's laws. it enables the law of segregation and the law of independent assortment

the study of heritable traits, or a stable change of cell function that happen without changes to the DNA sequence

single genes have more than one effect

sickle cell disease

cystic fibrosis and sickle cell

mucus build up, nutrients not absorbed well, bronchitis, bacterial infections

blood vessels clogged, weakness, pain, organ damage

genes carried on the sex chromosomes

the inactive X chromosome in female somatic cells. the coat of a calico cat is a classic visual example of this

female who carries an X-linked trait but does not express it. males cannot be carriers because of their Y chromosome, they will simply have to express the trait