Week 12 · Readings & resources

Week 12 — Readings & Resources

Introduction to Biology Free sample edition

Your primary reading is Chapter 12 (in this module). Everything below is the optional, go-deeper layer — pick what helps, skip the rest.

How to use this page

This page has 11 items (5 readings and 6 videos). Allow 59–72 minutes for everything. Each group points back to the matching chapter section and class-session segment, so use the full menu when you want more, or take the quick path below.

Every video here has captions: turn them on with the CC button in the player. The chapter covers the same ideas in text.

Pick-one quick path (16–21 min total)

① A blend or both at once?

Chapter 12, Section “Spot both at once: codominance” · Session 1, Segment 4, “Both at once: codominance” · Remember: a blend partway between the parents is incomplete dominance; two full versions side by side is codominance.

Incomplete Dominance — sci-ology — a short video on a heterozygote whose look falls between the two homozygotes, with a cross worked in a Punnett square; check its ratio against the chapter's 1 red : 2 pink : 1 white. This builds on Week 11's work with predicting the outcomes of crosses as probabilities. (video, 3 min) (captions: creator)
Co-dominance — sci-ology — a companion video on heterozygotes that show both versions at once; as you watch, ask the chapter's one question about each example: a blend, or both at once? (video, 3 min) (captions: creator)
Intro to Genetics: Why Your Cat Looks Like That: Crash Course Biology #31 — CrashCourse — a lively episode on alleles and patterns of inheritance, with chapters you can jump between; the incomplete dominance and codominance chapters near the end match this week, and the earlier parts are a quick review of last week. (video, 12 min) (captions: creator)

② Three alleles and the blood-type puzzle

Chapter 12, Section “Solve the blood-type puzzle” · Session 2, Segment 6, “The blood-type puzzle” · Remember: each parent passes one allele, not a blood type, so two parents who each carry a hidden i can have a type O child.

Does a child usually have the same blood type as one of their parents? — The Tech Interactive — a science museum's ask-a-geneticist answer that walks through the ABO gene's three versions and uses Punnett squares to show how a child can have a blood type neither parent has; compare its letters with the chapter's Iᴬ, Iᴮ, and i. Use it while working through the Week-12 module overview. (reading, 3–5 min)
ABO Blood Types: Codominance & Multiple Alleles Decoded — Ms. Parrott Science — a teacher's walk-through of the A, B, and O alleles, the antigens they make, and several blood-type crosses; it names the enzyme behind the antigens, which this course does not test, so keep your eye on the genotypes and the boxes. (video, 8 min) (captions: automatic)

③ Genes on the X and reading a family chart

Chapter 12, Section “Work the carrier cross” · Session 2, Segment 8, “The carrier cross” · Remember: a son's X comes from his mother, so a carrier mother and an unaffected father have half their sons affected and no daughters affected.

X-linked Inheritance and Punnett Squares — Dr Matt & Dr Mike — a whiteboard explanation of why a recessive allele on the X shows in males with one copy, with Punnett squares for the crosses; work the carrier-mother cross yourself before the video does. (video, 5 min) (captions: automatic)
Sex-Linked Inheritance Problem Set — The Biology Project — a set of short multiple-choice problems on genes carried on the X, each with a brief explanation, including human examples and the offspring of carrier mothers; the first few problems use fruit flies, and the same rules apply. (reading, 10–15 min)
What are the different ways a genetic condition can be inherited? — MedlinePlus — a plain-language page from the National Library of Medicine that lays out the main inheritance patterns side by side; read the entries for autosomal recessive, X-linked recessive, and codominance, and skip the rest. Stop here before DNA structure and replication; next week takes that up. (reading, 5–8 min)
Color vision deficiency — MedlinePlus — a condition page on the standard example of an X-linked recessive trait; read the description and the inheritance section, and notice how the page explains why males are affected far more often. (reading, 4–6 min)
Pedigree Charts for beginners — MooMooMath and Science — a short introduction to pedigree symbols and to following a trait from one generation to the next; afterward, make the chapter's two decisions in order on the worked family. (video, 5 min) (captions: automatic)

Optional one-stop reference (free online reference)

X-Linked — National Human Genome Research Institute Talking Glossary — the course's free glossary of genetic terms, open at its entry on X-linked traits; read the short definition, and treat the narration as optional. (reading, 1–2 min)

Heads-up (links rot): these point to outside sites that occasionally move or rename pages. If a link ever fails, tell your instructor and use the reference above in the meantime.

Provenance: Built with The Course Maker · samples.thecoursemaker.com