Chapter 3: Principles of Genetics

Who formed the foundational work on genetics?

Gregor Mendel

What did Mendel’s experiment show?

shows how dominant and recessive traits reveal predictable patterns.

What did Mendel’s P1 generation show?

yellow seed represents dominant seed color, and green seed represents the recessive seed color. this established clear parental traits. 

What happened when Mendel crossed yellow and green peas?

It showed that yellow seeds were more dominant than green seeds. 

What is Mendel’s Law of Segregation?

Traits separate during reproduction and traits can reappear. 

What is a punnett square?

Tools used in biotechnology to predict inheritance patterns of traits.

How are punnett squares used in biotechnology?

Punnett squares are used to predict the probability of offspring inheriting specific traits

What is the Law of independent Assortment?

Shows that the inheritance of one trait (shape) does not affect the color. 

Why is the Law of independent Assortment important in Biotechnology?

To understand how traits, genetic disorders, are inherited independently. 

What is a testcross?

A tool to determine whether an individual showing a dominant trait is homozygous or heterozygous.

What is homozygous?

Two identical alleles

What is heterozygous?

Two different alleles

Why are testcrosses important in Biotechnology?

To identify carriers of genetic traits and predicting the inheritance of disease.

What is incomplete dominance?

When the dominant trait does not completely mask the recessive trait

What does incomplete dominance show in Biotechnology?

shows how traits blend when no single allele is completely dominant.

What is codominance?

a genetic trait where both alleles for a gene are expressed equally and distinctly in an organism's phenotype, with neither allele masking the other

What is an example of a trait determined by codominance?

Human blood type (A,B,AB,O)

Why is codominance important in Biotechnology?

Important for medicine, transfusions, and paternity tests.

What is polygenic inheritance?

a pattern where multiple genes, not just one, contribute to a single trait

What is a classic example of polygenic inheritance?

skin color, height, weight

What type of results does polygenic inheritance produce?

A range or gradient of phenotypes. 

How is sex determined?

The combination of sex chromosomes

Why is sex determination important in Biotechnology?

prenatal testing.

How are sex linked traits determined? 

Controlled by genes on X chromosomes

Why are males more likely to express X-linked disorders?

Bceause males have only one X choromosome

How do females express sex linked disorders?

Females do not show symptoms.

Why is it important to understand sex-linked inheritance in Biotechnology? 

for predicting and managing genetic disorders, developing targeted therapies, and advancing diagnostic tools

What are chromosomal alterations?

large-scale changes in the structures of chromosomes

What is deletion?

one segment is missing, chromosome is shorter.

What is inversion?

re-arrange gene order without losing material

What is translocation?

a type of chromosome mutation where a part of one chromosome breaks off and attaches to a different chromosome, or to another part of the same chromosome

What is duplication?

a mutation where a segment of a chromosome is copied, resulting in extra genetic material

What is crossing over?

the process where homologous chromosomes exchange segments of their DNA, which occurs during meiosis to create new combinations of genes

Why is crossing over important in science and biotechnology?

variabilty in populations, evolution

When does crossing over occur?

prophase I of meiosis

What is nondisjunction?

the failure of chromosomes or sister chromatids to separate properly during cell division (mitosis or meiosis), resulting in daughter cells with an incorrect number of chromosomes

What is the result of nondisjunction?

aneuploidy, a condition where daughter cells have an abnormal number of chromosomes

What diseases does nondisjunction help explain?

Downs syndrome, Turner syndrome, and Klinefelter syndrome.

What is down’s syndrome?

a genetic condition caused by the presence of an extra copy of chromosome 21

What is turner syndrome?

a genetic condition that affects females, causing them to be born with only one complete X

What is Klinfelter syndrome?

a genetic disorder that occurs when a male is born with an extra X chromosome (47,XXY), leading to small testicles and low testosterone levels