Chapter 3: Principles of Genetics

Who formed the foundational work on genetics?

Gregor Mendel

What did Mendel’s experiment show?

How traits are passed from one generation to the next

What did Mendel’s P1 generation show?

It showed the parental traits

What happened when Mendel crossed yellow and green peas?

No peas were green in the F1 generation, showing that yellow peas were dominant

What is Mendel’s law of Segregation?

traits separate during reproduction and recessive traits can reappear

What is a punnet square?

A monohybrid cross used to predict the inheritance of traits

How are punnet squares used in biotechnology?

to predict the inheritance of traits

What is the Law of Independent Assortment?

inheritance of one trait does not affect the other

Why is the Law of Independent Assortment important in biotechnology?

understanding how traits and disorders are inherited independently

What is a testcross?

a tool to demonstrate whether dominant individuals are homozygous or heterozygous

What is homozygous?

when you have either two recessive alleles or two dominant alleles

What is heterozygous?

one dominant allele and one recessive allele

Why are test crosses important in biotechnology?

they help identify carriers of genetic traits and predicting inheritance of diseases

What is incomplete dominance?

When neither one trait is dominant over the other so a blended phenotype is shown

What does incomplete dominance show in biotechnology?

it’s important for plant breeding and medicine

What is codominance?

When neither allele is dominant over the other so both phenotypes or shown

What is an example of a trait determines by codominance?

blood type

Why is codominance important in biotechnology?

it’s important for medicine, transfusions, and paternity testing

What is polygenic inheritance?

When multiple genes affect one 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

How is sex determined?

The combination of sex chromosomes (x and y)

Why is sex determination important in biotechnology?

allows us to view inheritance, genetic disorders linked to sex chromosomes, and prenatal testing

How are sex linked traits determined?

whether an x chromosome carries a trait

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

Because they only have one x chromosome

How do females express sex linked disorders?

by having two x chromosomes that carry the trait.

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

to understand how certain conditions like color blindness are inherited

What are chromosomal alterations?

large-scale changes in the structure of chromosomes

WHat is deletion?

1 segment of DNA is missing

What is inversion?

rearrangements of gene orders without losing materials

What is translocation?

certain segment of one chromosome switches with another segments of a chromosome

What is duplication?

duplicating one segment of a gene

What is crossing over?

exchanging DNA between homologous chromosomes

Why is crossing over important in science and biotechnology?

it provides a foundation for evolution and selective breeding in biotechnology

When does crossing over occur?

meiosis

What is nondisjunction?

the failure of chromosomes to separate properly during meiosis

What is the result of nondisjunction?

gametes with too many or too few chromosomes

What diseases does nondisjunction help explain

• down syndrome

• turner syndrome

• klinefelter syndrome

What is Down’s Syndrome?

when someone has trisomy ( an extra chromosome)

What is Turner Syndrome?

absence or partial absence of an x chromosome - affects women

What is Klinefelter Syndrome?

an extra x chromosome in males (XXY)