Complex Inheritance

This set of flashcards covers complex inheritance concepts, including biological sex determination, sex-linked traits, inheritance patterns such as incomplete dominance and codominance, the role of environment and genetics in traits, and genetic abnormalities.

What is the primary factor that determines biological sex in humans?

The set of chromosomes inherited from parents.

What chromosomes do females have?

Females have XX chromosomes.

What chromosomes do males have?

Males have XY chromosomes.

How many pairs of chromosomes do humans have?

Humans have 23 pairs of chromosomes.

What hormone is primarily produced by testes in males?

Testosterone.

What hormone is primarily produced by ovaries in females?

Estrogen.

What is the role of the SRY gene on the Y chromosome?

It signals the development of testes.

What is the frequency of intersex births in the United States?

Approximately 1 in 1,500 births.

What is a common cause of conditions like color blindness in males?

X-linked inheritance.

What is the prevalence of red-green color blindness in males?

Approximately 7% of the male population.

What is the prevalence of red-green color blindness in females?

Approximately 0.4% of women.

What disorder is predominantly inherited through X-linked recessive patterns affecting males?

Hemophilia.

What is an X-linked trait?

A phenotype determined by the allele on an X chromosome.

What is an example of an X-linked disorder?

Duchenne muscular dystrophy (DMD).

What is incomplete dominance?

A form of inheritance where heterozygotes exhibit a phenotype that is intermediate between homozygous forms.

What genetic condition exemplifies incomplete dominance?

Familial hypercholesterolemia (FH).

What are polygenic traits?

Traits determined by the interaction of multiple genes.

What is an example of a polygenic trait in humans?

Height.

What does multifactorial mean in the context of traits?

Traits influenced by both genetics and the environment.

What is epigenetics?

The study of how the environment influences gene expression.

What is methylation in genetics?

The attachment of -CH3 groups to DNA, which can reduce gene expression.

What is the relation between identical twins and genetic traits?

Identical twins share 100% of their DNA and can reveal how genetics influence traits.

What is the condition caused by having an extra chromosome 21?

Down syndrome.

What process causes aneuploidy?

Nondisjunction during meiosis.

What is the term for when chromosomes do not separate properly during cell division?

Nondisjunction.

How can we determine if a fetus is aneuploid?

Through procedures like amniocentesis.

What type of genetic analysis can identify extra or missing chromosomes in fetal cells?

Karyotype analysis.

What is the frequency of Klinefelter syndrome?

1 in 1,000 males.

What are the characteristics of Turner syndrome?

Females with a single X chromosome, often infertile.

What is the outcome of a mating between a woman with mild FH (Hh) and a man with severe FH (HH)?

Children can display severe, mild, or normal phenotypes.

What do blood types A and B exhibit an example of?

Codominance.

What blood type is considered a universal donor?

Type O negative.

What does Rh factor determine in blood?

The presence or absence of specific proteins on red blood cells.

What is a key characteristic of codominance?

Both alleles contribute equally and separately to the phenotype.

How does the body produce high cholesterol in FH?

Cells do not make enough LDL receptors.

What is the result of environmental factors on gene expression?

It can lead to varying traits depending on environmental conditions.

What is the average associated height concordance in identical twins?

89%.

What can increased methylation of genes cause in terms of health?

Higher potential for anxiety or stress-related disorders.

What can occur if a fetus has an extra Y chromosome?

47, XYY syndrome, which can involve elevated learning disabilities.

What can happen to children if their mothers groom them less frequently?

Their GR gene can become more methylated.

What is the effect of proper maternal care on a child's GR gene?

Less methylation leading to normal cortisol levels.

In terms of genetic analysis, what does a pedigree show?

The occurrence and inheritance of traits across generations.

What can identify familial relationships through genetic markers?

Y-chromosome analysis.

What describes the inheritance of traits that blend in offspring?

Incomplete dominance.

What is an autosome?

Any chromosome that is not a sex chromosome.

What are the implications of genetic diversity in traits?

It results in continuous variation for traits like height.

What is a sex-linked genetic disorder?

A disorder associated with genes on sex chromosomes.

What is a factor influencing sex-linked inheritance?

Differences in probabilities of inheritance between sexes.

What happens in the absence of a Y chromosome during development?

The fetus will develop into a female.

What do sisters inherit genetically from their parents?

Two X chromosomes, one from each parent.

What role does testosterone play in male development?

It promotes the development of male sexual anatomy.

What is a defining feature of multifactorial traits?

Interactions between multiple genes and environmental factors.